Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/08/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
317 PM MDT SAT APR 6 2013
.SHORT TERM...QG LIFT ASSOCIATED WITH UPPER TROUGH TO OUR WEST IS
JUST BEGINNING TO IMPINGE ON THE WESTERN SECTIONS OF THE CWA PER
THE LATEST RAP ANALYSES. THIS ASCENT WILL SPREAD OVER THE
REMAINDER OF THE CWA OVERNIGHT BRINGING A THREAT OF PRECIPITATION
TO ALL AREAS...THE HIGHEST IN THE MOUNTAINS. HOWEVER...SATELLITE
AND RADAR TRENDS ARE LESS THAN IMPRESSIVE WITH THIS SYSTEM AND
HAVE CUT BACK ON POPS/QPFS ACCORDINGLY. AS THE SYSTEM HEADS EAST
LATER TONIGHT SOME DESCENT SUBSIDENCE WILL COVER THE CWA FOR MUCH
OF SUNDAY`S DAYLIGHT HOURS. LATEST HIRES WINDOW RUNS SHOW ONLY
ISOLATED CONVECTIVE ACTIVITY EAST OF THE MOUNTAINS SUNDAY
AFTERNOON AND HAVE BACKED OFF POPS THERE DUE TO THIS. MOREOVER...
NOT EXPECTING MORE THAN SCATTERED CONVECTIVE ACTIVITY IN THE
MOUNTAINS SUNDAY AFTERNOON EITHER. MAXIMUM TEMPERATURES TOMORROW
LOOK TO BE CLOSE TO THOSE EXPERIENCED TODAY.
.LONG TERM...SKIES WILL BE CLEARING SUNDAY NIGHT AS SUBSIDENCE
MOVES IN WITH NEAR NORMAL MINIMUM TEMPERATURES.
FOCUS TURNS TO MONDAY THROUGH TUESDAY AS AN EARLY SPRING STORM
AFFECTS THE STATE. MODELS IN MUCH BETTER AGREEMENT THAN THEY WERE
24 HOURS AGO...BUT STILL HAVE DIFFERENCES THAT MAY AFFECT HOW
MUCH SNOW WE SEE. HOWEVER...NO MATTER WHAT SOLUTION IS
FOLLOWED...HAVE HIGH CONFIDENCE IN GETTING PRECIPITATION AND GOOD
CONFIDENCE IN SIGNIFICANT SNOWFALL TOTALS.
WILL START MONDAY MORNING OUT DRY WITH INCREASING HIGH CLOUDS.
TEMPERATURES WILL AGAIN CLIMB INTO THE 60S FOR THE PLAINS AND NEAR
50 FOR THE MOUNTAINS. LATE MORNING INTO THE EARLY AFTERNOON...GOOD
INSTABILITY WILL ALLOW SHOWERS AND SOME THUNDERSTORMS BEGIN
FORMING. A RIDGE OF THETA E WILL BE SLIDING NORTH INTO EASTERN
COLORADO AND WESTERN KANSAS WITH CAPES IN THE 800-1200 J/KG RANGE.
GOOD SHEAR WILL COMBINE WITH THESE PARAMETERS TO BRING A CHANCE
OF STRONG THUNDERSTORMS OVER THE EASTERN PLAINS....MAINLY EAST OF
A LINE FROM STERLING TO LIMON. THE STORMS WILL HAVE THE POTENTIAL
TO PRODUCE LARGE HAIL AND PERHAPS A TORNADO...THOUGH RIGHT NOW
THIS LOOKS TO HAVE A BETTER CHANCE JUST EAST OF OUR FORECAST AREA.
MONDAY EVENING...THE STORMS 500 MB LOW CENTER WILL BE OVER THE
UT/AZ BORDER MOVING TOWARD THE FOUR CORNERS AREA...WITH THE
DEEPENING SURFACE LOW MOVING INTO SOUTHEASTERN COLORADO. THIS WILL
BEGIN TO DRAW IN THE COLD AIRMASS FROM THE NORTH. LOW LEVEL
MOISTURE FROM THE GULF THAT MOVED IN FROM THE SOUTH EARLIER IN THE
DAY WILL COMBINE WITH THE MID LEVEL MOISTURE FROM THE PACIFIC WITH
THIS SYSTEM AS THE STORM MOVES OVERHEAD MONDAY NIGHT.
PRECIPITATION WILL BEGIN OVER THE PLAINS AS RAIN...AND DEPENDING
ON HOW FAST THE COLD AIR MOVES IN...WILL DETERMINE WHEN THE RAIN
CHANGES OVER TO SNOW. FOR NOW...FOLLOWING MORE OF THE GFS AND
ECMWF SOLUTIONS FOR A QUICKER COOL DOWN COMPARED TO THE NAM. THE
NAM SOLUTION OVERALL SEEMS A LITTLE TOO FAR NORTH. SNOW...HEAVY AT
TIMES...IS EXPECTED TO SPREAD SOUTH OVER THE AREA MONDAY NIGHT
INTO EARLY TUESDAY MORNING. THE BEST UPSLOPE LOOKS TO OCCUR OVER
THE NORTHERN HALF OF THE FORECAST AREA...SO WILL EXPECT TO SEE THE
HIGHER AMOUNTS NORTH OF I-70...AND LIKELY EAST OF I-76. RIGHT
NOW...EXPECT A BROAD BRUSH 5-12 INCHES WITH SOME HIGHER AMOUNTS
POSSIBLE OVER THE NORTHERN FOOTHILLS AND URBAN CORRIDOR. HOWEVER
DOWN OVER SOUTHERN LINCOLN COUNTY AND IN THE HIGH MOUNTAIN
VALLEYS...WILL SEE 2-5 INCHES WHERE THERE WILL BE SLIGHT
DOWNSLOPING EFFECTS. THE HARD PART OF THE SNOW FORECAST IS THE
TEMPERATURES...AS THE WARM TEMPERATURES OF MONDAY WILL DEFINITELY
MELT THE INITIAL SNOW AND AREAS OVER THE EASTERN TO CENTRAL
EASTERN PLAINS MAY TAKE A LOT LONGER TO CHANGE OVER TO SNOW. IF WE
WERE IN THE DEAD OF WINTER...WE WOULD BE TALKING ABOUT ALMOST 2
FEET OF SNOW. BUT HERE WE ARE IN SPRING WITH WARMING GROUND
TEMPERATURES AND PRE-STORM AIR TEMPS IN THE 60S. THIS WILL PLAY
WITH THE SNOW- AMOUNT FORECAST COMPARED TO THE QPF.
TUESDAY...AS COLD AIR CONTINUES TO POUR IN...NORTH WINDS WILL BE
BLOWING AT 15 TO 25 MPH WITH GUSTS UP TO 35 MPH...WHICH WILL
PRODUCE BLOWING AND DRIFTING SNOW OVER THE PLAINS. AS THIS EVENT
GETS CLOSER...WILL HAVE TO SEE IF AND WHAT KIND OF A HIGHLIGHT
WILL BE NEEDED...AS THE WINDS COULD BE STRONG ENOUGH FOR A
BLIZZARD...DEPENDING ON HOW THE SYSTEM WRAPS UP.
SNOW SHOULD DIMINISH TUESDAY EVENING AS THE SYSTEM MOVES
NORTHEAST INTO NEBRASKA. AS SKIES CLEAR AND COLD AIR CONTINUES TO
MOVE IN IN NORTHERLY FLOW ALOFT...LOW TEMPERATURES TUESDAY NIGHT
WILL LIKELY BE IN THE SINGLE DIGITS TO TEENS AND HIGHS WEDNESDAY
WILL STRUGGLE TO GET MUCH ABOVE FREEZING. GFS IS STILL HANGING ON
TO ANOTHER WEAK DISTURBANCE MOVING THOUGH THURSDAY....HAVE KEPT
THE SLIGHT CHANCE POPS IN THE FORECAST. WILL BEGIN TO RETURN TO
NORMAL TEMPERATURES INTO THE WEEKEND WITH A GENERALLY DRY
PATTERN...EXCEPT FOR MOUNTAIN SHOWERS IN NORTHWEST FLOW ALOFT.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED AT AREA TERMINALS
OVERNIGHT AND TOMORROW. THERE STILL MAY BE PUSH OF WESTERLY WINDS
LATE THIS AFTERNOON AND EARLY EVENING WITH SPEEDS PERHAPS TOUCHING
25 KNOTS FOR A WHILE. DIURNAL WINDS EXPECTED OVERNIGHT WITH
WESTERLY COMPONENTS MOST OF SUNDAY. AS THE UPPER TROUGH MOVES
OVERHEAD TONIGHT AND EARLY SUNDAY THERE MAY BE SOME CEILINGS
AROUND 8000 FEET ALONG WITH ISOLATED SHOWERS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...ET
LONG TERM....KRIEDERMAN
AVIATION...ET
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1239 AM EDT SAT APR 6 2013
.SYNOPSIS...
HIGH PRESSURE FROM THE GREAT LAKES REGION WILL BUILD EAST OVERNIGHT,
MOVING OFF THE COAST LATE SATURDAY. A COLD FRONT IS EXPECTED TO
APPROACH EARLY MONDAY, THEN STALL IN OUR VICINITY LATE MONDAY
THROUGH TUESDAY. THIS FRONT MAY THEN MOVE NORTH AS A WARM FRONT BY
MIDWEEK. A MORE VIGOROUS COLD FRONT IS EXPECTED LATE THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLEAR SKIES ARE FORECAST FOR TONIGHT.
FOR THE MIDNIGHT NEAR-TERM UPDATE...HOURLY TEMPS WERE ADJUSTED
SOMEWHAT OVER INTERIOR SRN NJ AS NLY WINDS HAVE KEPT UP AND THE
EXPECTED RADIATIONAL COOLING OVER THE PINE BARRENS HAS YET TO
DEVELOP. HWVR...THE RAP MODELS SUGGESTS A RIDGE OF HIGH PRES OVER
THE AREA TOWARDS MORNING SO WINDS MAY DROP OFF AND RAPID COOLING
OCCUR AT THAT TIME. SO OVERNIGHT MINS WERE NOT CHANGED.
SINCE THE GROWING SEASON HAS STARTED OVER THE CENTRAL DELMARVA
AND OUR FORECAST TEMPERATURES ARE AROUND THE FREEZING MARK, WE HAD
TO CONSIDER A FROST ADVISORY OR FREEZE WARNING. THE WINDS THERE
SHOULD REBOUND SOME OVERNIGHT, BUT THE MORE SHELTERED AREAS COULD
SEE THEIR WINDS GO LIGHT AGAIN BEFORE DAYBREAK. WE`VE ISSUED A
FROST ADVISORY IN RESPONSE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TODAY/...
SATURDAY LOOKS TO BE A GREAT DAY WITH HIGH PRESSURE OVERHEAD AND
HARDLY A CLOUD. THE WIND WILL SHIFT FROM NW EARLY TO SW LATE AND
SHOULD BE 10 MPH OR LESS. TEMPS WILL REBOUND INTO THE MID TO UPPER
50S ONCE AGAIN.
&&
.LONG TERM /TONIGHT THROUGH FRIDAY/...
THE LONG TERM PORTION OF THIS FORECAST PACKAGE BEGINS WITH A
ZONAL FLOW PATTERN IN THE MID-PORTIONS OF THE ATMOSPHERE WHICH
BECOMES MORE SOUTHWESTERLY THROUGH MIDWEEK AS A TROUGH DEEPENS IN
THE WESTERN PART OF THE COUNTRY. MODEL GUIDANCE SUGGESTS THIS
TROUGH THEN LOSES SOME OF ITS NEGATIVE AMPLIFICATION AS IT MOVES
TOWARD THE EAST COAST BY FRIDAY. AT THE SURFACE, HIGH PRESSURE
ALONG THE EAST COAST WILL DRIFT SLOWLY EASTWARD ON SUNDAY AS A
COLD FRONT, ASSOCIATED WITH A LOW PRESSURE SYSTEM MOVING THROUGH
EASTERN CANADA, TRIES TO PASS THROUGH. A BLOCKING PATTERN WILL
LIKELY PREVENT THIS FRONT FROM MAKING CLEAR PASSAGE, WHICH MEANS
IT COULD HANG UP ACROSS OUR REGION LATE MONDAY AND A GOOD PART OF
TUESDAY. EVENTUALLY THIS FRONT SHOULD MOVE NORTH AGAIN AS A WARM
FRONT LATE TUESDAY OR EARLY WEDNESDAY. THEN A MORE VIGOROUS COLD
FRONT, ASSOCIATED WITH THE MID-LEVEL TROUGH, APPROACHES EARLY
THURSDAY, EVENTUALLY MOVING OFF THE COAST THURSDAY NIGHT. THIS
COLD FRONT COULD BRING THE FIRST THREAT OF CONVECTIVE WEATHER THIS
SPRING SEASON.
ALL THIS BOILS DOWN TO NORMAL TO ABOVE NORMAL TEMPERATURES THROUGH
THE PERIOD...WITH SOME SHOWERS POSSIBLE LATE SUNDAY INTO MIDWEEK,
WITH THE POSSIBILITY OF WIDESPREAD CONVECTIVE ACTIVITY NEAR THE END
OF THE WORKWEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDS ARE EXPECTED THRU THE TAF PD.
HIGH PRESSURE WAS BUILDING IN FROM THE NW AND WILL BE WITH US INTO
THE WEEKEND. SOME GUSTINESS UP NORTH MAY EVENTUALLY MAKE IT`S WAY
SOUTH, BUT GENERALLY A MODERATE NORTH FLOW IS EXPECTED THROUGH
DAYBREAK. EXPECT NLY FLOW EARLY TMRW TO BECOME MORE SWLY LATER ON
SAT WITH SPEEDS GENLY 10 KT OR LESS.
OUTLOOK...
SATURDAY NIGHT...VFR.
SUNDAY AND SUNDAY NIGHT...MAINLY VFR. CHANCE OF SHOWERS MAINLY
NORTHWEST AIRPORTS LATER IN THE DAY AND AT NIGHT. SOUTH WINDS
10-20 KNOTS DURING THE DAY WITH SOME HIGHER GUSTS.
MONDAY AND TUESDAY...MAINLY VFR. WIDELY SCATTERED TO SCATTERED MVFR
SHOWERS POSSIBLE NEAR A STALLING FRONT.
WEDNESDAY...MAINLY VFR.
&&
.MARINE...
CONDITIONS WERE SUB-ADVISORY LATE THIS EVENING, BUT WE STILL SEE
GUIDANCE FORECASTING A WINDOW OF ADVISORY WINDS AND SEAS TONIGHT.
WE HAVE MAINTAINED THE ADVISORY. HIGH PRESSURE FROM THE NW WILL
KEEP A NWLY FLOW OVER THE AREA THRU THE FIRST HALF OF SAT, THEN
THE WIND SHOULD GRADUALLY BECOME MORE SWLY LATER ON SAT. THE WIND
SPEEDS WILL GRADUALLY DIMINISH THOUGH AS THE HIGH BUILDS CLOSER
AND THE PGRAD RELAXES.
OUTLOOK...
SCA CONDITIONS ARE POSSIBLE ON SUNDAY WITH BOTH WINDS AND SEAS IN
RESPONSE TO A SOUTHWEST FLOW ALONG THE EAST COAST AHEAD OF AN
APPROACHING COLD FRONT. CONDITIONS SHOULD THEN SETTLE DOWN TO
SUB-SCA CRITERIA THROUGH MIDWEEK.
&&
.FIRE WEATHER...
SATURDAY WILL BE ANOTHER DRY DAY, BUT WIND SPEEDS WON`T BE AS
STRONG AS THEY WERE TODAY. NO HEADLINES ARE ANTICIPATED.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...FROST ADVISORY FROM 5 AM TO 8 AM EDT THIS MORNING FOR DEZ002-
003.
MD...FROST ADVISORY FROM 5 AM TO 8 AM EDT THIS MORNING FOR MDZ012-
015-019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...MIKETTA
NEAR TERM...AMC
SHORT TERM...NIERENBERG
LONG TERM...MIKETTA
AVIATION...NIERENBERG/MIKETTA
MARINE...NIERENBERG/MIKETTA
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
908 PM EDT Sun Apr 7 2013
.NEAR TERM [Through Tonight]... With return flow moisture off of the
Gulf of Mexico combined with a decent Sea Breeze today, a fairly
sizable CU field was able to be generated. Both temps and dewpoints
responded well to the warming early Spring sunshine, with highs
reaching the upper 70s to lower 80s in most locations. The remnants
of the CU field have dissipated rapidly with the loss of insolation,
so a mostly clear and mild evening is in store for the CWA. With a
bit more in the way of low level moisture, and low temps only
expected to fall into the middle 50s, this may open the door for
some patchy fog and areas of low cloudiness to develop overnight.
Patchy fog is already in the grids for the western half of the CWA,
and may tweak this and sky just a bit to the current fcst.
Otherwise, everything is on track. In fact, increased sky cover for
low clouds quite a bit over the western half of the CWA.
&&
.SHORT TERM [Tonight Through Wednesday]... The large scale
longwave pattern commences early Monday with trough over Wrn
states and weak ridging extending over Ern states. At surface,
main features are low over TX/OK Panhandle with frontal boundary
SWD bisecting TX and a large surface ridge from the Wrn Atlc SWWD
across Gulf coastal states with axis just to our N and into the
Gulf of Mex. Through the day, the trough will amplify SEWD over
Rockies, Desert SW and adjacent Old Mex. In response, Ern
mid/upper ridge with rising heights will build over SE region.
Atlc surface shifts SWD with ridge axis becoming more WLY so low
level veers to SE to S increasing low level moisture/clouds and
humidity. The onshore flow and building ridge will bring above
seasonal temperatures to the region.
During Tuesday, Wrn trough fully developed with low over 4 Corners
early lifting to W/Cntrl Plains by sundown. In response, Ern ridge
builds further over SE region. On Wednesday, low begins to lift NEWD
to NE Plains and opens up shunting se ridge SEWD towards Wrn Atlc
with increasing sly aloft over SE region. By Wed morning, surface
low across Mo with cold front SSW thru Cntrl TX with local surface
ridge retreating into Atlc. So period marked by increasing temps/
clouds and humidities and veering winds, however rain remains to
our west thru short term. Expect inland highs on Monday to be in the
lower 80s rising to the mid 80s Tues and Wed. Lows Mon and Tues
night will be in the mid to upper 50s. Patchy fog is possible each
late night into the early morning period.
&&
.LONG TERM [Wednesday Night through Sunday]...
The tranquil short term pattern will begin to change during the late
work week. However, inconsistencies continue between the global
models with the GFS and Canadian remaining 6-12 hrs faster in
developing and moving key features. This far out will blend models
for timing. So on Wed night into Thurs, above trough/low lifts into
the Great Lakes with increasingly SWLY deep layer moisture
overspreading local region. By Thurs night, trough across Ern
states. Surface low lifts into OH Valley with front SWWD thru Ern MS
and into Wrn Gulf moving Ewd to bisect our CWFA around sunrise Fri
where absent any push begins to slow down and then possibly stalls.
But by Fri aftn, upper features begins to lift newd, and fronts
crosses W-E with drier air overspreading region from W-E.
While this system may be a potent severe weather producer in the Mid
Mississippi River Valley, the bulk of the dynamical forcing will be
shifting rapidly through the Ohio Valley and thus greatly limit our
organized severe potential with this system. Still, some models are
showing impressive H85 Jet so can discount strong to an isold severe
storms Thurs eve into Fri. Then, expect high pressure building into
region with fair weather rest of period.
Will go with 30-0% NW-SE pop gradient Wed night, 60-50% on Thurs,
40% Thurs night and 20-30% on Fri. Otherwise Nil pops. Inland Min
temps will commence Wed night in the low to mid 60s, drop to 55-60
Thurs night and 45-55 degrees in wake of front Fri night before
rising about 5 degrees each Sat and Sun nights. Inland Max temps
will commence above climo, 78 west to 83 east dropping to normal
readings, mid to upper 70s Fri and Sat and near 80 on Sun.
&&
.AVIATION [through 12 UTC Monday]...
The latest guidance offers conflicting signals about the potential
for low cigs Monday morning, with MOS (especially GFS MOS)
forecasting widespread IFR/LIFR cigs around dawn Monday, and the
SREF and HRRR keeping any cigs west of our forecast area. Our 00 UTC
package leans more toward the optimistic SREF/HRRR, which follows
persistence and climo more closely. We expect any IFR cigs to be
limited to KECP, with mainly VFR conditions elsewhere. Other than
the temporary low cigs at KECP, VFR conditions will prevail through
Monday evening.
&&
.MARINE...
Current obs show light ESE winds with 2 seas. Prevailing winds will
be from the southeast 15 knots or less tonight at least through
Wednesday. Winds and seas will be a little higher across the western
waters, especially Thursday and Thursday night where cautionary
level conditions are expected ahead of an approaching cold front. In
wake of the front, expect moderate offshore flow into weekend.
&&
.FIRE WEATHER...
With onshore flow expected for much of the week, red flag conditions
are not expected. However, with high mixing heights and modest
transport winds, dispersion values will continue to be elevated.
&&
.HYDROLOGY...
No rainfall is anticipated until at least Thursday of the upcoming
week. Rivers will remain in recession with the Aucilla likely
dropping below flood stage on Sunday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 55 81 57 84 60 / 0 0 0 0 10
Panama City 61 78 63 80 62 / 0 0 0 0 10
Dothan 56 82 59 84 59 / 0 0 0 0 10
Albany 56 82 59 85 59 / 0 0 0 0 10
Valdosta 55 82 57 85 61 / 0 0 0 0 10
Cross City 54 81 56 84 61 / 0 0 0 0 10
Apalachicola 59 75 61 76 62 / 0 0 0 0 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Block
LONG TERM...Block
AVIATION...Fournier
MARINE...Gould/Block
FIRE WEATHER...DVD
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
812 PM EDT SUN APR 7 2013
.UPDATE...
A MID TO UPPER LEVEL TROUGH MOVED THROUGH THE FLORIDA PENINSULA
THIS AFTERNOON ALLOWING FOR A FEW SHOWERS TO DEVELOP OVER THE
AREA. THE TROUGH WILL CONTINUE TO MOVE EAST AWAY FROM SOUTH
FLORIDA TONIGHT...AS THE SURFACE HIGH REMAINS OVER THE WESTERN
ATLANTIC WATERS. THIS WILL ALLOW FOR DRY AIR TO WORK BACK INTO THE
AREA FOR TONIGHT. SO WILL KEEP THE WEATHER DRY OVER SOUTH FLORIDA
TONIGHT ALONG WITH MOSTLY CLEAR TO CLEAR SKIES. TEMPERATURES
TONIGHT SHOULD BE ABLE TO FALL INTO THE 60S TONIGHT OVER SOUTH
FLORIDA...DUE TO THE CLEAR SKIES AND LIGHT WINDS OVERNIGHT.
SO THE ONLY CHANGE TO THE FORECAST FOR TONIGHT IS TO REMOVE THE
AFTERNOON AND EVENING WORDING FROM THE ZONES.
&&
.UPDATE...54/BNB
.PREV DISCUSSION... /ISSUED 739 PM EDT SUN APR 7 2013/
AVIATION...
HIGH PRESSURE JUST TO THE EAST CONTINUES TO KEEP VFR CONDITIONS
TONIGHT AND INTO TOMORROW. IT WILL ALSO KEEP EAST TO SOUTHEAST
FLOW OVER SOUTH FLORIDA THROUGH THE TAF PERIOD. THE EXCEPTION WILL
BE A WEAK SEA BREEZE AT KAPF TOMORROW AFTERNOON. WINDS WILL RANGE
FROM LIGHT AND VARIABLE TO EAST SOUTHEAST BETWEEN 5 AND 10 KTS
TONIGHT. THEY WILL PICK UP OUT OF THE EST SOUTHEAST TOMORROW
AROUND 10 TO 15 WITH GUSTS TO AROUND 20 KTS. ANOTHER ROUND OF VFR
TO POSSIBLE MVFR CIGS TOMORROW AFTERNOON.
&&
PREV DISCUSSION... /ISSUED 219 PM EDT SUN APR 7 2013/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
PLACED AN ISOLATED POP GRID FOR ALL ZONES THE REMAINDER OF THIS
AFTERNOON. THE ONSHORE FLOW OF A FEW SHOWERS ALONG THE EAST COAST
HAS BEEN PERSISTENT AND THE HRRR DOES INDICATE A CONTINUATION OF
ISOLATED ACTIVITY DEVELOPING ACROSS THE INTERIOR AND COASTAL
COLLIER COUNTY UNTIL VERY EARLY THIS EVENING.
GLOBAL MODELS IN VERY GOOD AGREEMENT OVER THE NEXT 48-60 HOURS
WITH MID LEVEL ZONAL FLOW THROUGH EARLY TUESDAY AND SURFACE HIGH
PRESSURE ACROSS THE ATLANTIC AND NORTH FLORIDA. THIS WILL MAINTAIN
A MODEST EASTERLY LOW LEVEL WIND FLOW AND A MOSTLY DRY WEATHER
REGIME WITH STRONG SUBSIDENCE CAP REMAINING INTACT. THERE IS A
SMALL INCREASE IN PWAT VALUES THAT WILL BE ROTATING WESTWARD
BENEATH THE LARGE SCALE LOW LEVEL RIDGE OVER THE ATLANTIC THAT THE
MODELS SHOW ARRIVING ACROSS SOUTH FLORIDA BY LATE TUESDAY AND
TUESDAY NIGHT. FORECAST SOUNDINGS ALSO INDICATE THE CAP WILL BEGIN
TO ERODE BY THIS TIME AND THIS SHOULD ALLOW FOR A SLIGHT INCREASE
IN SHOWER ACTIVITY MOVING FROM THE ATLANTIC ONTO THE SOUTHEAST
COAST. FOR THIS REASON, WILL MAINTAIN A SLIGHT CHANCE POP ALONG
THE EAST COAST TUESDAY NIGHT AND SILENT POP ELSEWHERE AS RAIN
CHANCES OVER THE INTERIOR AND COASTAL COLLIER COUNTY WILL BE TOO
SMALL TO MENTION IN THOSE LOCATIONS. IN ADDITION, THE SHORT RANGE
ENSEMBLE (SREF) IS SHOWING A SUBSTANTIAL INCREASED CHANCE FOR FOG
OVER THE INTERIOR AND SOUTHWEST COAST FOR MONDAY NIGHT AND TUESDAY
NIGHT AS THE LOW LEVEL MOISTURE INCREASES SO WILL INTRODUCE PATCHY
FOG FOR THOSE LOCATIONS AT THAT TIME.
LONG TERM (WEDNESDAY THROUGH SUNDAY)...
LOOKING AHEAD TOWARDS THE MIDDLE AND END OF THE WEEK, THE FORECAST
BECOMES INCREASINGLY UNCERTAIN AS THE GFS AND ECMWF CONTINUE TO
DIVERGE ON THE EVOLUTION OF THE POWERFUL MID LEVEL TROUGH THAT WILL
BE MOVING INTO THE CENTRAL PLAINS STATES MONDAY NIGHT AND TUESDAY
THEN SHIFTING EAST THROUGH THE WEEK. THE GFS PHASES IT IN WITH A
NORTHERN STREAM TROUGH BY LATE WEDNESDAY AND THURSDAY AS THE MAIN
SYSTEM LIFTS EAST INTO THE ATLANTIC. THIS BRINGS A TRAILING COLD
FRONT ACROSS SOUTH FLORIDA ON FRIDAY SLOWLY PUSHING THROUGH THE
REGION AND OFF THE SOUTHEAST COAST LATE SATURDAY AND SUNDAY. THIS
WOULD ALSO BRING AN INCREASED CHANCE FOR CONVECTION ON FRIDAY AND
POSSIBLY LINGERING INTO SATURDAY AS SHOWN BY THE LATEST MEX
GUIDANCE. HOWEVER, THE ECMWF IS ALSO HOLDING ONTO ITS SLOWER
SOLUTION WITH THE CENTRAL PLAINS TROUGH PHASING WITH THE UPSTREAM
SYSTEM BUT FARTHER TO THE NORTH. IT THEN SHOWS THE FRONT STALLING
ACROSS CENTRAL FLORIDA SATURDAY AND SUNDAY SO THE HIGHEST POPS WOULD
BE OVER NEXT WEEKEND. AT THIS TIME, IT IS A WAIT AND SEE APPROACH
WITH LITTLE CHANGE TO THE CURRENT FORECAST.
MARINE...
WIND AND SEAS WILL REMAIN BELOW ADVISORY LEVELS THROUGH THE END OF
THIS WEEK WITH A LIGHT TO MODERATE EAST TO SOUTHEAST WIND AND SEAS
OF 5 FEET OR LESS. THE WIND WILL INCREASE AND BECOME MORE
SOUTHERLY BY FRIDAY AS A COLD FRONT MOVES INTO NORTH FLORIDA AND
THE HIGH PRESSURE SHIFTS FARTHER EAST INTO THE ATLANTIC.
FIRE WEATHER...
RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL THRESHOLDS
THROUGH THE END OF THIS WEEK AS LOW LEVEL MOISTURE WILL CONTINUE
TO INCREASE. THIS WILL ALSO INCREASE THE LIKELIHOOD FOR SOME LATE
NIGHT FOG FORMATION OVER THE INTERIOR AND SOUTHWEST COAST AS THE
WEEK PROGRESSES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 67 80 69 81 / - - 10 10
FORT LAUDERDALE 70 80 70 82 / - - 10 10
MIAMI 68 77 71 82 / - - 10 10
NAPLES 65 81 65 84 / - - - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
739 PM EDT SUN APR 7 2013
.AVIATION...
HIGH PRESSURE JUST TO THE EAST CONTINUES TO KEEP VFR CONDITIONS
TONIGHT AND INTO TOMORROW. IT WILL ALSO KEEP EAST TO SOUTHEAST
FLOW OVER SOUTH FLORIDA THROUGH THE TAF PERIOD. THE EXCEPTION WILL
BE A WEAK SEA BREEZE AT KAPF TOMORROW AFTERNOON. WINDS WILL RANGE
FROM LIGHT AND VARIABLE TO EAST SOUTHEAST BETWEEN 5 AND 10 KTS
TONIGHT. THEY WILL PICK UP OUT OF THE EST SOUTHEAST TOMORROW
AROUND 10 TO 15 WITH GUSTS TO AROUND 20 KTS. ANOTHER ROUND OF VFR
TO POSSIBLE MVFR CIGS TOMORROW AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 219 PM EDT SUN APR 7 2013/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
PLACED AN ISOLATED POP GRID FOR ALL ZONES THE REMAINDER OF THIS
AFTERNOON. THE ONSHORE FLOW OF A FEW SHOWERS ALONG THE EAST COAST
HAS BEEN PERSISTENT AND THE HRRR DOES INDICATE A CONTINUATION OF
ISOLATED ACTIVITY DEVELOPING ACROSS THE INTERIOR AND COASTAL
COLLIER COUNTY UNTIL VERY EARLY THIS EVENING.
GLOBAL MODELS IN VERY GOOD AGREEMENT OVER THE NEXT 48-60 HOURS
WITH MID LEVEL ZONAL FLOW THROUGH EARLY TUESDAY AND SURFACE HIGH
PRESSURE ACROSS THE ATLANTIC AND NORTH FLORIDA. THIS WILL MAINTAIN
A MODEST EASTERLY LOW LEVEL WIND FLOW AND A MOSTLY DRY WEATHER
REGIME WITH STRONG SUBSIDENCE CAP REMAINING INTACT. THERE IS A
SMALL INCREASE IN PWAT VALUES THAT WILL BE ROTATING WESTWARD
BENEATH THE LARGE SCALE LOW LEVEL RIDGE OVER THE ATLANTIC THAT THE
MODELS SHOW ARRIVING ACROSS SOUTH FLORIDA BY LATE TUESDAY AND
TUESDAY NIGHT. FORECAST SOUNDINGS ALSO INDICATE THE CAP WILL BEGIN
TO ERODE BY THIS TIME AND THIS SHOULD ALLOW FOR A SLIGHT INCREASE
IN SHOWER ACTIVITY MOVING FROM THE ATLANTIC ONTO THE SOUTHEAST
COAST. FOR THIS REASON, WILL MAINTAIN A SLIGHT CHANCE POP ALONG
THE EAST COAST TUESDAY NIGHT AND SILENT POP ELSEWHERE AS RAIN
CHANCES OVER THE INTERIOR AND COASTAL COLLIER COUNTY WILL BE TOO
SMALL TO MENTION IN THOSE LOCATIONS. IN ADDITION, THE SHORT RANGE
ENSEMBLE (SREF) IS SHOWING A SUBSTANTIAL INCREASED CHANCE FOR FOG
OVER THE INTERIOR AND SOUTHWEST COAST FOR MONDAY NIGHT AND TUESDAY
NIGHT AS THE LOW LEVEL MOISTURE INCREASES SO WILL INTRODUCE PATCHY
FOG FOR THOSE LOCATIONS AT THAT TIME.
LONG TERM (WEDNESDAY THROUGH SUNDAY)...
LOOKING AHEAD TOWARDS THE MIDDLE AND END OF THE WEEK, THE FORECAST
BECOMES INCREASINGLY UNCERTAIN AS THE GFS AND ECMWF CONTINUE TO
DIVERGE ON THE EVOLUTION OF THE POWERFUL MID LEVEL TROUGH THAT WILL
BE MOVING INTO THE CENTRAL PLAINS STATES MONDAY NIGHT AND TUESDAY
THEN SHIFTING EAST THROUGH THE WEEK. THE GFS PHASES IT IN WITH A
NORTHERN STREAM TROUGH BY LATE WEDNESDAY AND THURSDAY AS THE MAIN
SYSTEM LIFTS EAST INTO THE ATLANTIC. THIS BRINGS A TRAILING COLD
FRONT ACROSS SOUTH FLORIDA ON FRIDAY SLOWLY PUSHING THROUGH THE
REGION AND OFF THE SOUTHEAST COAST LATE SATURDAY AND SUNDAY. THIS
WOULD ALSO BRING AN INCREASED CHANCE FOR CONVECTION ON FRIDAY AND
POSSIBLY LINGERING INTO SATURDAY AS SHOWN BY THE LATEST MEX
GUIDANCE. HOWEVER, THE ECMWF IS ALSO HOLDING ONTO ITS SLOWER
SOLUTION WITH THE CENTRAL PLAINS TROUGH PHASING WITH THE UPSTREAM
SYSTEM BUT FARTHER TO THE NORTH. IT THEN SHOWS THE FRONT STALLING
ACROSS CENTRAL FLORIDA SATURDAY AND SUNDAY SO THE HIGHEST POPS WOULD
BE OVER NEXT WEEKEND. AT THIS TIME, IT IS A WAIT AND SEE APPROACH
WITH LITTLE CHANGE TO THE CURRENT FORECAST.
MARINE...
WIND AND SEAS WILL REMAIN BELOW ADVISORY LEVELS THROUGH THE END OF
THIS WEEK WITH A LIGHT TO MODERATE EAST TO SOUTHEAST WIND AND SEAS
OF 5 FEET OR LESS. THE WIND WILL INCREASE AND BECOME MORE
SOUTHERLY BY FRIDAY AS A COLD FRONT MOVES INTO NORTH FLORIDA AND
THE HIGH PRESSURE SHIFTS FARTHER EAST INTO THE ATLANTIC.
FIRE WEATHER...
RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL THRESHOLDS
THROUGH THE END OF THIS WEEK AS LOW LEVEL MOISTURE WILL CONTINUE
TO INCREASE. THIS WILL ALSO INCREASE THE LIKELIHOOD FOR SOME LATE
NIGHT FOG FORMATION OVER THE INTERIOR AND SOUTHWEST COAST AS THE
WEEK PROGRESSES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 67 80 69 81 / - - 10 10
FORT LAUDERDALE 70 80 70 82 / - - 10 10
MIAMI 68 77 71 82 / - - 10 10
NAPLES 65 81 65 84 / - - - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
240 PM EDT SAT APR 6 2013
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE IMPRESSIVE APRIL TROUGH
RESPONSIBLE FOR THE RAIN AND COLD FRONT ON FRIDAY CONTINUES TO PULL
EAST OF THE FL PENINSULA. ASSOCIATED COOL POOL ALOFT IS ALSO
QUICKLY TRANSLATING EASTWARD. BEHIND THIS TROUGH...HEIGHT FIELDS ARE
REBOUNDING RAPIDLY RESULTING IN MID/UPPER LEVEL RIDGING OVERHEAD BY
THIS EVENING. AT THE SURFACE...FORECAST AREA RESIDES ON THE SOUTHERN
PERIPHERY OF A LARGE RIDGE EXTENDING DOWN THE EASTERN SEABOARD.
TEMPERATURES ARE CLIMBING THROUGH THE 70S UNDER A MIX OF SUN AND A
SCT-BKN CUMULUS FIELD. THIS CU FIELD IS FORCED BY THE DIURNAL
HEATING INTERACTING WITH A SHALLOW MOIST LAYER BELOW 825MB...AND
SHOULD GENERALLY DISSIPATE AS WE HEAD TOWARD MID/LATE EVENING.
&&
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
NOT MUCH IN THE WAY OF SENSIBLE WEATHER ON THE WAY THROUGH THE EARLY
PORTION OF THE FORECAST PERIOD...WITH NO SIGNIFICANT WEATHER
POTENTIAL UNTIL NEAR THE END OF THE WEEK.
TONIGHT/SUNDAY/SUNDAY NIGHT...
WEAK MID/UPPER RIDGE WILL PASS OVER AND EAST OF THE REGION BY SUNDAY
MORNING WITH A MORE ZONAL FLOW DEVELOPING ALONG THE NORTHERN GULF
COAST AND FL PENINSULA IN IT WAKE. AT THE SURFACE...THE REGION WILL
REMAIN ON THE SOUTHERN SIDE OF A RIDGE AXIS EXTENDING DOWN/JUST OFF
THE EASTERN CONUS SEABOARD. DRY CONDITIONS WILL BE THE RULE WITH
LITTLE TO NO SYNOPTIC FORCING OR AVAILABLE MOISTURE KEEPING POPS
NEAR ZERO FOR THE REST OF THE WEEKEND. LOW TEMPERATURES BY LATE
TONIGHT WILL BE SEASONABLY COOL WITH MANY INLAND LOCATIONS DROPPING
INTO THE 50S...AND THE IMMEDIATE COAST FROM PINELLAS COUNTY
SOUTHWARD HOLDING IN THE 60S.
SUNDAY WILL FEATURE OF MIX OF SUN AND CLOUDS WITH ANOTHER LATE
MORNING/AFTERNOON EXPANDING CU FIELD. EFFICIENT MIXING UP TO AROUND
850-825MB WHERE TEMPS WILL BE AROUND 10-12C SHOULD ALLOW MANY
LOCATIONS AWAY FROM THE BEACHES TO APPROACH 80 OR EVEN CLIMB INTO
THE LOWER 80S SOUTH OF I-4. THE IMMEDIATE COAST MAY END UP SEVERAL
DEGREES COOLER WHERE FEEBLE AFTERNOON SEA-BREEZE CIRCULATIONS WILL
TURN WINDS ONSHORE FOR PART OF THE PEAK HEATING PERIOD.
SUNDAY NIGHT WILL FEATURE MOSTLY CLEAR SKIES AND TEMPERATURES A FEW
DEGREES COOLER THAN TONIGHT. MAINLY LOOKING FOR LOWS DROPPING INTO
THE UPPER 50S TO LOWER 60S BY SUNRISE...WITH SOME MIDDLE 50S FOR THE
NORMALLY COLDER SPOTS ALONG THE NATURE COAST.
MONDAY-TUESDAY...
THE WARMING TREND CONTINUES INTO THE EARLY PORTION OF THE WEEK.
TEMPERATURES WILL QUICKLY RISE BACK ABOVE NORMAL FOR MANY
SPOTS...ESPECIALLY BY TUESDAY. GFS/ECMWF SHOW ZONAL FLOW AGAIN
BECOMING WEAKLY RIDGED IN THE MID/UPPER LEVELS WHILE THE SURFACE
RIDGE AXIS SINKS EVER SO SLOWLY SOUTHWARD TOWARD THE GA/SC COAST.
EFFICIENT MIXING...STRONG APRIL SUN...AND A WARMING LOW LEVEL COLUMN
(850MB TEMPS 12-14C) WILL ALLOW MANY LOCATIONS AWAY FROM THE COAST
TO MIX OUT INTO THE LOWER 80...AND EVEN SO MIDDLE 80S SOUTH OF TAMPA
MONDAY AFTERNOON. MANY SPOTS ARE FORECAST TO REACH THE MIDDLE 80S
AWAY FROM THE BEACHES FOR TUESDAY AFTERNOON. ENJOY THE PLEASANT
APRIL WEATHER!
&&
.LONG TERM (TUESDAY THROUGH NEXT SATURDAY)...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH WEDNESDAY OR
WEDNESDAY NIGHT...WITH SOLUTIONS THEN DIVERGING SIGNIFICANTLY WITH
RESPECT TO THE NEXT COLD FRONT LATE NEXT WEEK AND INTO THE UPCOMING
WEEKEND. THE 00Z CANADIAN AND 00Z ECMWF SOLUTIONS SHOW A MUCH LESS
PROGRESSIVE PATTERN...WITH THE 00Z GFS AND 00Z UKMET SOLUTIONS MUCH
MORE AGGRESSIVE MOVING THE NEXT COLD FRONT INTO THE FORECAST AREA AS
EARLY AS THURSDAY NIGHT. WILL TAKE A BLENDED FORECAST APPROACH FOR
NOW AS BOTH SOLUTIONS SEEM TO HAVE SOME MERIT GIVEN THE SPREAD IN
THE GFS ENSEMBLE SUITE. OVERALL...WILL KEEP THE FORECAST RAIN FREE
THROUGH TUESDAY NIGHT...WITH SLIGHT CHANCE LOW CHANCE POPS IN THE
FORECAST EACH DAY WEDNESDAY THROUGH SATURDAY FOR PRIMARILY
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS. TEMPERATURES ARE
EXPECTED TO RUN ABOVE NORMAL THROUGH FRIDAY BEFORE SETTLING BACK
CLOSER TO SEASONAL LEVELS NEXT WEEKEND.
&&
.AVIATION...
VFR CONDITIONS WITH OCNL BKN VFR CIGS. LIMITED LATE NIGHT BR
POSSIBLE AT LAL/PGD/RSW. NE OR NORTH WINDS AND GUST AT TIMES
DIMINISH OVER NIGHT AND BECOME NE AND EAST.
&&
.MARINE...
THE REGION WILL REMAIN ON THE SOUTHERN SIDE OF A RIDGE AXIS ALONG
THE EASTERN SEABOARD THROUGH THE EARLY PORTION OF NEXT WEEK. THIS
POSITION WITH RESPECT TO THE RIDGE WILL PROVIDE A GENERAL EAST TO
SOUTHEAST FLOW REGIME ACROSS THE EASTERN GULF OF MEXICO...OUTSIDE
OF LOCAL ONSHORE FLOW DURING THE AFTERNOON ASSOCIATED WITH ANY
SEA-BREEZE CIRCULATIONS.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED OVER THE NEXT
COUPLE OF DAYS. RELATIVE HUMIDITY VALUES AWAY FROM THE COAST ARE
FORECAST TO BRIEFLY APPROACH 35 PERCENT BOTH SUNDAY AND MONDAY
DURING THE AFTERNOON...HOWEVER NO CRITICAL DURATIONS OF LOW RELATIVE
HUMIDITY ARE EXPECTED AND RED FLAG CONDITIONS APPEAR UNLIKELY.
INCREASING LOW LEVEL MOISTURE FOR THE MIDDLE PORTION OF THE WEEK
SHOULD PREVENT CRITICAL LEVELS OF RELATIVE HUMIDITY FOR ALL ZONES.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 61 78 63 83 / 10 0 10 0
FMY 61 82 63 85 / 10 10 0 0
GIF 59 82 61 85 / 10 10 0 10
SRQ 60 80 61 82 / 10 10 0 0
BKV 52 82 55 84 / 10 10 10 10
SPG 64 79 66 83 / 10 10 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1025 AM EDT SAT APR 6 2013
.UPDATE...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE IMPRESSIVE APRIL TROUGH
RESPONSIBLE FOR THE RAIN AND COLD FRONT ON FRIDAY IS NOW QUICKLY
PULLING EAST OF THE FL PENINSULA. ASSOCIATED COOL POOL ALOFT IS ALSO
QUICKLY TRANSLATING EASTWARD. BEHIND THIS TROUGH...HEIGHT FIELDS
WILL REBOUND QUITE RAPIDLY THROUGH THE REMAINDER OF THE DAY
RESULTING IN MID/UPPER LEVEL RIDGING OVERHEAD BY THIS EVENING. AT
THE SURFACE...FORECAST AREA RESIDES ON THE SOUTHERN PERIPHERY OF A
LARGE RIDGE EXTENDING DOWN THE EASTERN SEABOARD. 12Z KTBW SOUNDING
PROFILE SHOWED A STILL RATHER COOL LOW LEVEL AIRMASS IN PLACE...AND
THIS IS RESULTING A SLOW DIURNAL TEMPERATURE RISE THIS MORNING
REGARDLESS OF THE EFFICIENT MIXING UNDERWAY. RAP FORECAST IS RIGHT
ON TRACK WITH THIS SLOW MORNING WARMING...BUT ALSO SHOWS A DECENT
1000-850MB COLUMN RECOVERY INTO THE AFTERNOON. WOULD EXPECT WITH
THIS COLUMN TEMP RECOVERY TO SEE A MORE RAPID TEMPERATURE REBOUND
OVER THE UPCOMING SEVERAL HOURS. FORECAST HIGH TEMPERATURES MAY
STILL BE A BIT OPTIMISTIC IN SOME PLACES...BUT FEEL BY LATE
AFTERNOON WE WILL BE MAKING AT LEAST A RUN AT THE CURRENT FORECAST
TEMPS...AND SO WILL HOLD OFF ON ANY MAJOR UPDATES.
SKIES HAVE BECOME MOSTLY CLEAR THIS MID-MORNING ACROSS THE REGION
AND THIS MAY HOLD FOR ANOTHER HOUR OR 2. HOWEVER...TIME HEIGHT AND
CROSS SECTION ANALYSIS CONTINUE TO SHOW A DECENT MOISTURE LAYER IN
PLACE THROUGH THE AFTERNOON BETWEEN 950-825MB. AS THE COLUMN MIXING
CONTINUES...WOULD EXPECT A SCT-BKN CUMULUS FIELD TO DEVELOP WITHIN
THE NORTHEAST FLOW AND OVERSPREAD FOR MUCH OF THE AFTERNOON.
MADE SOME MINOR ADJUSTMENTS TO THE WINDS/TEMPS/DEWPOINTS THROUGH THE
OVERNIGHT HOURS...BUT OTHERWISE INHERITED FORECAST APPEARS ON TRACK.
HAVE A GREAT SATURDAY!
&&
.AVIATION...
LIMITED MVFR CIGS GIVE WAY MID-MORNING TO SCT-BKN VFR CIGS THAT
CONTINUE INTO THE EVENING. NORTH OR NE WINDS WILL BE GUSTY AT
TIMES.
&&
.MARINE...
THE REGION WILL REMAIN ON THE SOUTHERN SIDE OF A RIDGE AXIS ALONG
THE EASTERN SEABOARD THROUGH THE EARLY PORTION OF NEXT WEEK. THIS
POSITION WITH RESPECT TO THE RIDGE WILL PROVIDE A GENERAL EAST TO
SOUTHEAST FLOW REGIME ACROSS THE EASTERN GULF OF MEXICO...OUTSIDE
OF LOCAL ONSHORE FLOW DURING THE AFTERNOON ASSOCIATED WITH ANY
SEA-BREEZE CIRCULATIONS.
&&
.FIRE WEATHER...
BASED ON MINOR TEMPERATURE AND DEWPOINT UPDATES THIS MORNING...MANY
LOCATIONS AWAY FROM THE IMMEDIATE COAST ARE FORECAST TO BRIEFLY
APPROACH OR REACH 35 PERCENT RELATIVE HUMIDITY THIS AFTERNOON.
CRITICAL DURATIONS OF THESE LOW READINGS AND RED FLAG CONDITIONS ARE
NOT EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 61 80 63 / 0 0 0 10
FMY 80 61 83 63 / 0 0 0 10
GIF 78 58 82 61 / 0 0 0 10
SRQ 77 60 81 65 / 0 0 0 10
BKV 77 52 81 59 / 0 0 0 10
SPG 76 63 81 64 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
517 PM CDT SAT APR 6 2013
.DISCUSSION...
259 PM CDT
THERE ARE NUMEROUS CHALLENGES WITH THE FORECAST AS THE PATTERN
TRANSITIONS TO A MORE ACTIVE ONE...BEGINNING WITH SHOWERS AND
SOME SPORADIC THUNDER THIS EVENING AND THEN CARRYING THROUGH THE
MIDDLE OF NEXT WEEK. IN ADDITION...THE LIKELY LOCATION OF THE
AREA RELATIVE TO SYNOPTIC FEATURES WILL ALLOW FOR TEMPERATURES TO
BE HEAVILY DEPENDENT ON CLOUD COVER AND RAIN...ALONG WITH LAKE
INDUCED COOLING AT LEAST A FEW OF THE UPCOMING SEVERAL DAYS.
NEAR TERM INTO TONIGHT...A FAST PACED BUT MORE AMPLIFIED UPPER
LEVEL PATTERN IS ESTABLISHED OVER THE CENTRAL U.S. THIS AFTERNOON
WITH A WELL-DEFINED UPPER WAVE ON WATER VAPOR ADVANCING EASTWARD
FROM WESTERN IA. A 1000 MB SURFACE LOW REFLECTION ACROSS SOUTHERN
MN HAS DEVELOPED AND HELPED TO ESTABLISH STRONG RETURN FLOW WITH
WIND GUSTS TO 40 TO 45 MPH AT SEVERAL SITES. THESE WINDS SHOULD
DIMINISH GRADUALLY THROUGH THE EVENING HOURS.
MOISTURE RETURN HAS STRUGGLED HOWEVER...BOTH AT THE SURFACE AND IN
THE DEEP LAYER PER OBSERVATIONS AND PWAT ANALYSIS AND IS A REASON
SHOWER COVERAGE IS LIKELY TO BE MORE LIMITED THAN IT COULD BE
GIVEN THE UPPER FORCING AHEAD OF THIS WAVE...AND IT WILL TAKE SOME
TIME FOR THE VERY DRY LOWER ATMOSPHERE TO SATURATE. A NARROW
CORRIDOR OF 700-900 MB MOISTURE TRANSPORT ALONG A MID-LEVEL JET
HAS STILL HELPED TO INCREASE ECHOES UPSTREAM DURING THE FIRST HALF
OF THE AFTERNOON AND THIS WILL LIKELY BE JUST ENOUGH TO CONTINUE
DOING SUCH WITH STEEPENING MID-LEVEL LAPSE RATES IN CONCERT WITH
THE NARROW MOISTURE CONVERGENCE. MOST OF THE HIGH-RES CONVECTIVE
ALLOWING MODELS PREDICT AN INCREASE IN CONVECTIVE-TYPE ECHOES
ACROSS NORTH CENTRAL IL BETWEEN 23Z AND 03Z SHIFTING EASTWARD AND
FADING SLOWLY THROUGH EARLY OVERNIGHT AS THE FRONT SHIFTS EAST.
WITH SEVERAL OF THESE GUIDANCE MEMBERS INDICATING HIGHER
REFLECTIVITY AND A NARROW CORRIDOR OF 200-400 J/KG OF MUCAPE PER
THE RAP ALONG THE FRONT...WOULD EXPECT A FEW STORMS WITHIN THE
GENERAL SHOWERS. HAVE ADAPTED HOURLY POPS THROUGH THIS EVENING
PERIOD OF THE FORECAST. AS PREVIOUS FORECAST DID KEEP MOST OF
TONIGHTS TEMPERATURE DROP AFTER THE FRONTAL PASSAGE FROM WEST TO
EAST.
SUNDAY...HIGH PRESSURE STILL LOOKS TO BRIEFLY PREVAIL FOR THIS
PERIOD. THE MOST NOTEWORTHY ASPECT ABOUT THIS IS IT LOOKS TO LINE
UP DOWN THE AXIS OF LAKE MICHIGAN BY MIDDAY AND ALLOW FOR A FAIRLY
STOUT LAKE BREEZE. THIS WILL BE AIDED BY THE FACT THAT
TEMPERATURES SHOULD MODERATE NICELY ON SUNDAY OVER LAND DUE TO
ONLY A SMALL WINDOW OF COLD AIR ADVECTION BEHIND THE FRONT TONIGHT
AND A DRY AIR MASS AND PREDICTED SUNSHINE DURING SUNDAY. THE
TEMPERATURE AND PRESSURE DIFFERENCES WITHIN A LIGHT WIND FIELD
SHOULD DRIVE A STRONG LAKE BREEZE...AND THE AFTERNOON TEMPERATURE
DROP FOR DOWNTOWN CHICAGO AND OTHER NEAR LAKE AREAS MAY BE AS MUCH
AS 15 DEGREES.
SUNDAY NIGHT AND MONDAY...AN ACTIVE WEST-TO-EAST PACIFIC JET OVER
120 KT AS SEEN ON HEMISPHERIC WATER VAPOR TODAY WILL DIG ITS WAY
INTO THE WESTERN U.S. WITH TROUGH DEVELOPMENT AND UPSTREAM
SOUTHWEST FLOW OVER THE MIDWEST. A LEAD IMPULSE IN THIS FLOW IS
WELL PREDICTED ON GUIDANCE TO PASS OVER THE AREA DURING LATE
SUNDAY NIGHT INTO MONDAY MORNING. THIS LOOKS TO TIGHTEN AN UPPER
LEVEL WARM FRONT AND ALLOW FOR SATURATED ISENTROPIC LIFT FOR RAIN
SHOWERS. ELEVATED INSTABILITY DOES INCREASE AS THE WARM NOSE
BUILDS IN WITHIN THE LOWER LEVELS...AND START THUNDER IN THIS
FORECAST PERIOD ITS TOO TOUGH TO DISCERN A PERIOD WHERE THERE
WOULD NOT BE A THUNDER CHANCE ALL THE WAY THROUGH WEDNESDAY NIGHT.
IN THE WAKE OF THIS LEAD IMPULSE HEIGHTS LOOK TO BUILD ON MONDAY
AS THE PRIMARY TROUGH DEVELOPS. ITS A LITTLE INTERESTING AS THERE
SHOULD BE A SURFACE WARM FRONT...POSSIBLY DIABATICALLY
ENHANCED...LAID OUT SOMEWHERE IN THE CENTRAL IL TO NORTHERN IL
REGION. THE ONLY THING IS WITH SHORT WAVE RIDGING HINTED AT THIS
FEATURE APPEARS TO BE FAIRLY BENIGN...BUT SOMETHING TO KEEP AN
EYE ON.
MIDWEEK...AN ACTIVE PERIOD HERE AS PROLONGED SURFACE CYCLOGENESIS
BEGINS OVER THE SOUTHERN PLAINS MONDAY NIGHT AND CONTINUES THROUGH
TUESDAY WITH THE SURFACE WAVE ADVANCING ENE ON WED. MODEL
GUIDANCE HAS COME INTO BETTER AGREEMENT WITH THIS...LATCHING MORE
ONTO AN EC SOUTHERN SOLUTION. HAVE CONTINUED TO LEAN THAT WAY WITH
THE FORECAST WHICH MEANS INHIBITING TEMPERATURES ON WHAT COULD BE
GIVEN 850MB TEMPERATURES CLIMBING TO 8C-12C...ESPECIALLY NORTH OF
I-80. WITH FLOW OFF THE LAKE TUESDAY AND WEDNESDAY DUE TO THE LOW
BEING SOUTHWEST OF THE AREA...TEMPERATURES NEAR THE LAKE WILL
REMAIN COOLER. ALSO THIS FORECAST PATTERN MEANS LIKELY SEVERAL
BOUTS OF PRECIP WITH THE PROXIMITY OF THE ELEVATED WARM/STATIONARY
FRONT. THE 06.12 GFS AND EC RUNS BOTH HAVE OVER TWO AND A HALF
INCHES OF RAIN FORECAST AREA WIDE FROM SUNDAY NIGHT THROUGH
THURSDAY. WHILE IT IS CHALLENGING TO FOCUS ANY WINDOW FOR
CATEGORICAL POPS...IT WOULD SEEM WEDNESDAY AND WEDNESDAY NIGHT
WOULD BE THE MOST FAVORED PERIODS FOR STRONGER DYNAMIC FORCING AND
POSSIBLY MORE ROBUST ELEVATED CONVECTION WITH THE LARGE SCALE
UPPER TROUGH MOVING EASTWARD. COOLING BEHIND THE FRONT LOOKS
SOMEWHAT STRONG AND THERE IS A POTENTIAL TO SEE SOME MIX IN THE
WAKE OF THE FRONT...BUT CONFIDENCE IS VERY LOW ON HOW THIS SYSTEM
WILL EVOLVE AS IT LIFTS OUT.
BEYOND...HAVE GONE PRIMARILY WITH A MODEL CONSENSUS AT THE END OF
NEXT WEEK AS THE UPPER FLOW PATTERN WORKS FROM BRIEFLY NORTHWEST
BACK TO WEST. TEMPERATURES SHOULD GRADUALLY MODERATE BUT
CONFIDENCE IS LOW ON PRECIP CHANCES AS THE PATTERN STILL LOOKS
DISTURBED.
MTF
&&
.FIRE WEATHER...
328 AM...EASTERLY FLOW HAS MAINTAINED MUCH DRIER AIR ACROSS THE
REGION AND EXPECT A SLOW RETURN OF LOW LEVEL MOISTURE ACROSS THE
AREA TODAY. IT APPEARS DEWPOINTS WILL INCREASE BACK INTO THE
40S...BUT PROBABLY NOT UNTIL LATE AFTERNOON ACROSS WESTERN IL AND
THE REST OF THE AREA THIS EVENING. THUS MINIMUM RH VALUES TODAY
WILL LIKELY BE IN THE 35-40 PERCENT RANGE AND COULD POSSIBLY DIP
INTO THE 30-35 PERCENT RANGE. WHILE THESE EXPECTED VALUES WILL
REMAIN ABOVE RED FLAG CRITERIA OF 25 PERCENT...SOUTHERLY WINDS ARE
EXPECTED TO QUICKLY INCREASE THIS MORNING WITH GUSTS AS HIGH AS 40
MPH FROM LATE MORNING THROUGH SUNSET WITH THE POTENTIAL FOR HIGHER
GUSTS. WHILE THERE COULD BE A FEW LIGHT SHOWERS OR SPRINKLES
TODAY...THE BEST TIMING FOR SHOWERS AND A FEW THUNDERSTORMS WILL
BE FROM LATE AFTERNOON THROUGH MID/LATE EVENING. TEN HOUR FUEL
MOISTURE DIPPED TO 8-9 PERCENT ON FRIDAY AND SIMILAR VALUES ARE
POSSIBLE TODAY. AS A RESULT...THERE WILL BE AN INCREASED FIRE
DANGER AND WHILE MEETING RED FLAG CRITERIA IS NOT EXPECTED...
CONDITIONS WILL NEED TO BE MONITORED THROUGH DAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* WINDS IN THE 190-210 DEGREE RANGE THROUGH EARLY EVENING WITH
GUSTS TO AROUND 35 KT UNTIL CLOSER TO SUNSET BEFORE EASING BACK
INTO THEM ID/UPPER 20 KT RANGE. HIGHER GUSTS POSSIBLE WITH
SHOWERS THOUGH.
* WINDS BEGIN TO TURN MORE SOUTHWESTERLY...PROBABLY AFTER
02/03Z...THEN TURN WEST-NORTHWEST WITH COLD FRONTAL PASSAGE
TOWARD 06/07Z.
* SCATTERED LIGHT RAIN SHOWERS RETURN TOWARD 00Z...WITH BEST
CHANCE FOR ORGANIZED SHOWERS AFTER 03Z...RUMBLE OF THUNDER ALSO
POSSIBLE.
* SHORT PERIOD OF MVFR CIGS POSSIBLE OVERNIGHT.
MDB
//DISCUSSION...UPDATED 22Z...
ONE BAND OF LIGHT RAIN IS WORKING ITS WAY AWAY FROM THE CHI
TERMINALS AT THIS TIME WITH ANOTHER BAND OF LIGHT SHOWERS JUST
EAST OF THE MISSISSIPPI RIVER. THESE SHOWERS WILL CROSS THE AREA
OVER THE NEXT FEW HOURS. THE COLD FRONT IS NOW STRETCHED FROM NEAR
KALO TO NEAR KMCI AND CONTINUES EASTWARD. HAVE SEEN SOME BETTER
CUMULUS DEVELOPMENT ON SATELLITE OVER THE LAST HOUR OR SO ALONG
THE FRONT WHICH SUPPORTS THE EXPECTATION THAT THE BEST CHANCE FOR
SHOWERS AND POSSIBLY SOME THUNDER WILL BE RIGHT ALONG THE FRONT
LATER THIS EVENING. MAY NEED TO SLOW TIMING SLIGHTLY WITH THE NEXT
TAF UPDATE.
OTHERWISE...SOUTH-SOUTHWEST WINDS CONTINUE TO GUST BUT SOME OF THE
RECENT HIGHER GUSTS MAY HAVE BEEN AIDED BY THE SHOWERS. OVERALL
FREQUENCY OF GUSTS OVER 30 KT SEEMS TO BE DECREASING WITH MID TO
UPPER 20S BECOMING MORE LIKELY OVER THE NEXT FEW HOURS. CANNOT
RULE OUT OCCASIONAL HIGHER GUSTS WITH THE SHOWER ACTIVITY THROUGH
MUCH OF THE EVENING THOUGH.
MDB
FROM 18Z...
AN AREA OF LOW PRESSURE LOCATED ACROSS EASTERN NEBRASKA WILL
CONTINUE TO LIFT NORTHEAST TOWARDS CENTRAL WISCONSIN TONIGHT.
AHEAD OF THIS SYSTEM...THE GRADIENT HAS TIGHTENED. THE COMBINATION
OF A TIGHT PRESSURE GRADIENT AND WARMTH AT THE SFC HAS ALLOWED
GUSTY SFC WINDS FROM THE SOUTH. GUSTS UP TO 35 KT HAVE BEEN
OBSERVED EARLY THIS AFTERNOON...AND IT APPEARS THIS WILL CONTINUE
THROUGH EARLY THIS EVENING BEFORE MARGINALLY DIMINISHING TO AROUND
25 TO 30KT. THE OTHER CHALLENGE FOR AVIATION PURPOSES IS IN
REGARDS TO THE TIMING OF PRECIP. GUIDANCE HAS STEADILY BACKED OFF
ON PRECIP TRENDS...NOW FOCUSED ON A 02-05Z ARRIVAL TIME FOR
ORD/MDW. FOR RFD IT APPEARS ARND 00Z FOR THE INITIAL MENTION OF
PRECIP LOOKS PROBABLE. THE ENVIRONMENT DOES BECOME UNSTABLE...AND
COULD ALLOW FOR AN ISOLATED THUNDERSTORMS THIS EVENING ALTHOUGH
CONFIDENCE HAS DIMINISHED BASED ON TIMING. IN ADDITION TO THE
POSSIBILITY OF PRECIPITATION AND THUNDER...CLOUDS WILL STEADILY
LOWER. AT THIS TIME IT APPEARS THE LOWEST CLOUDS WILL PROBABLY
TOUCH MVFR CONDS FOR A BRIEF PERIOD OVERNIGHT. AT THIS TIME THE
THINKING IS THAT CIGS WILL REDUCE TO ARND 3KFT AGL.
THE FRONTAL BOUNDARY WILL STEADILY APPROACH THE REGION THIS
EVENING...AND ALLOW WINDS TO SLOWLY TURN WESTERLY ACROSS NORTHERN
IL/NORTHWEST IN AIRFIELDS. DRIER AIR WILL STEADILY SLIDE EAST
ACROSS THE REGION...THIS ALLOW CLOUDS TO SLOWLY ERODE BY SUN LATE
MORNING. WINDS ARE ALSO EXPECTED TO STEADILY TURN NORTH THEN
NORTHEASTERLY BY MIDDAY SUN...HOWEVER SPEEDS WILL BE MUCH LIGHTER
WITH UP TO 10 KT EXPECTED.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN WIND DIRECTION TRENDS WITH MEDIUM-HIGH
CONFIDENCE IN TIMING.
* MEDIUM-HIGH CONFIDENCE IN GUSTS TO 35 KT BEFORE SUNSET BUT THEIR
FREQUENCY MAY DECREASE PRIOR TO THAT.
* HIGH CONFIDENCE IN BEST TIMING FOR RAIN CHANCES BUT MEDIUM
CONFIDENCE THAT TS POTENTIAL IS LOW.
* LOW CONFIDENCE IN CIGS LOWERING TO MVFR OVERNIGHT.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...SHRA/TSRA LIKELY LATE. MVFR PROBABLE SOME CHANCE OF
BRIEF IFR LATE.
MONDAY...SHRA/TSRA LIKELY EARLY. MVFR/BRIEF IFR POSSIBLE EARLY.
TUESDAY THROUGH THURSDAY NIGHT...PERIODIC CHANCE FOR SHRA/TSRA.
PERIODIC MVFR CIGS/VSBY LIKELY WITH BRIEF IFR POSSIBLE.
FRIDAY...PROBABLE VFR.
IZZI
&&
.MARINE...
241 PM CDT
LOW PRESSURE OVER SOUTHERN MINNESOTA THIS AFTERNOON IS LIFTING A
STRONG WARM FRONT ACROSS LAKE MICHIGAN TODAY. WINDS OVER THE LAND
ARE TOPPING OUT AROUND 35 KT THIS AFTERNOON WITH THESE GALES
EXTENDING INTO THE NEARSHORE WATERS WHERE A GALE WARNING REMAINS
IN EFFECT THROUGH THIS EVENING. HOWEVER...WITH TEMPERATURES
PUSHING 70 ACROSS NORTHERN ILLINOIS/INDIANA...VERY STABLE
CONDITIONS ARE SETTING UP OVER THE OPEN WATERS OF THE LAKE AND
SHOULD BE INHIBITING THE STRONGER GUSTS FROM REACHING THE LAKE
SURFACE. THE LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATE
THIS EVENING WITH A TRAILING COLD FRONT PUSHING ACROSS THE LAKE
SHORTLY THEREAFTER WITH WINDS TURNING WESTERLY AND DIMINISHING.
ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO MOVE INTO THE REGION
MIDWEEK...THOUGH MODELS CONTINUE TO STRUGGLE WITH TRACK AND TIMING
MAKING IT DIFFICULT TO PIN DOWN DETAILS REGARDING OVER THE LAKE.
CONTINUE TO FAVOR A FARTHER SOUTH SOLUTION SUPPORTED BY THE
CONSISTENT ECMWF...WHICH THE LATEST GFS HAS TRENDED TOWARDS.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...NEARSHORE WATERS UNTIL
10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
302 PM CDT SAT APR 6 2013
.DISCUSSION...
259 PM CDT
THERE ARE NUMEROUS CHALLENGES WITH THE FORECAST AS THE PATTERN
TRANSITIONS TO A MORE ACTIVE ONE...BEGINNING WITH SHOWERS AND
SOME SPORADIC THUNDER THIS EVENING AND THEN CARRYING THROUGH THE
MIDDLE OF NEXT WEEK. IN ADDITION...THE LIKELY LOCATION OF THE
AREA RELATIVE TO SYNOPTIC FEATURES WILL ALLOW FOR TEMPERATURES TO
BE HEAVILY DEPENDENT ON CLOUD COVER AND RAIN...ALONG WITH LAKE
INDUCED COOLING AT LEAST A FEW OF THE UPCOMING SEVERAL DAYS.
NEAR TERM INTO TONIGHT...A FAST PACED BUT MORE AMPLIFIED UPPER
LEVEL PATTERN IS ESTABLISHED OVER THE CENTRAL U.S. THIS AFTERNOON
WITH A WELL-DEFINED UPPER WAVE ON WATER VAPOR ADVANCING EASTWARD
FROM WESTERN IA. A 1000 MB SURFACE LOW REFLECTION ACROSS SOUTHERN
MN HAS DEVELOPED AND HELPED TO ESTABLISH STRONG RETURN FLOW WITH
WIND GUSTS TO 40 TO 45 MPH AT SEVERAL SITES. THESE WINDS SHOULD
DIMINISH GRADUALLY THROUGH THE EVENING HOURS.
MOISTURE RETURN HAS STRUGGLED HOWEVER...BOTH AT THE SURFACE AND IN
THE DEEP LAYER PER OBSERVATIONS AND PWAT ANALYSIS AND IS A REASON
SHOWER COVERAGE IS LIKELY TO BE MORE LIMITED THAN IT COULD BE
GIVEN THE UPPER FORCING AHEAD OF THIS WAVE...AND IT WILL TAKE SOME
TIME FOR THE VERY DRY LOWER ATMOSPHERE TO SATURATE. A NARROW
CORRIDOR OF 700-900 MB MOISTURE TRANSPORT ALONG A MID-LEVEL JET
HAS STILL HELPED TO INCREASE ECHOES UPSTREAM DURING THE FIRST HALF
OF THE AFTERNOON AND THIS WILL LIKELY BE JUST ENOUGH TO CONTINUE
DOING SUCH WITH STEEPENING MID-LEVEL LAPSE RATES IN CONCERT WITH
THE NARROW MOISTURE CONVERGENCE. MOST OF THE HIGH-RES CONVECTIVE
ALLOWING MODELS PREDICT AN INCREASE IN CONVECTIVE-TYPE ECHOES
ACROSS NORTH CENTRAL IL BETWEEN 23Z AND 03Z SHIFTING EASTWARD AND
FADING SLOWLY THROUGH EARLY OVERNIGHT AS THE FRONT SHIFTS EAST.
WITH SEVERAL OF THESE GUIDANCE MEMBERS INDICATING HIGHER
REFLECTIVITY AND A NARROW CORRIDOR OF 200-400 J/KG OF MUCAPE PER
THE RAP ALONG THE FRONT...WOULD EXPECT A FEW STORMS WITHIN THE
GENERAL SHOWERS. HAVE ADAPTED HOURLY POPS THROUGH THIS EVENING
PERIOD OF THE FORECAST. AS PREVIOUS FORECAST DID KEEP MOST OF
TONIGHTS TEMPERATURE DROP AFTER THE FRONTAL PASSAGE FROM WEST TO
EAST.
SUNDAY...HIGH PRESSURE STILL LOOKS TO BRIEFLY PREVAIL FOR THIS
PERIOD. THE MOST NOTEWORTHY ASPECT ABOUT THIS IS IT LOOKS TO LINE
UP DOWN THE AXIS OF LAKE MICHIGAN BY MIDDAY AND ALLOW FOR A FAIRLY
STOUT LAKE BREEZE. THIS WILL BE AIDED BY THE FACT THAT
TEMPERATURES SHOULD MODERATE NICELY ON SUNDAY OVER LAND DUE TO
ONLY A SMALL WINDOW OF COLD AIR ADVECTION BEHIND THE FRONT TONIGHT
AND A DRY AIR MASS AND PREDICTED SUNSHINE DURING SUNDAY. THE
TEMPERATURE AND PRESSURE DIFFERENCES WITHIN A LIGHT WIND FIELD
SHOULD DRIVE A STRONG LAKE BREEZE...AND THE AFTERNOON TEMPERATURE
DROP FOR DOWNTOWN CHICAGO AND OTHER NEAR LAKE AREAS MAY BE AS MUCH
AS 15 DEGREES.
SUNDAY NIGHT AND MONDAY...AN ACTIVE WEST-TO-EAST PACIFIC JET OVER
120 KT AS SEEN ON HEMISPHERIC WATER VAPOR TODAY WILL DIG ITS WAY
INTO THE WESTERN U.S. WITH TROUGH DEVELOPMENT AND UPSTREAM
SOUTHWEST FLOW OVER THE MIDWEST. A LEAD IMPULSE IN THIS FLOW IS
WELL PREDICTED ON GUIDANCE TO PASS OVER THE AREA DURING LATE
SUNDAY NIGHT INTO MONDAY MORNING. THIS LOOKS TO TIGHTEN AN UPPER
LEVEL WARM FRONT AND ALLOW FOR SATURATED ISENTROPIC LIFT FOR RAIN
SHOWERS. ELEVATED INSTABILITY DOES INCREASE AS THE WARM NOSE
BUILDS IN WITHIN THE LOWER LEVELS...AND START THUNDER IN THIS
FORECAST PERIOD ITS TOO TOUGH TO DISCERN A PERIOD WHERE THERE
WOULD NOT BE A THUNDER CHANCE ALL THE WAY THROUGH WEDNESDAY NIGHT.
IN THE WAKE OF THIS LEAD IMPULSE HEIGHTS LOOK TO BUILD ON MONDAY
AS THE PRIMARY TROUGH DEVELOPS. ITS A LITTLE INTERESTING AS THERE
SHOULD BE A SURFACE WARM FRONT...POSSIBLY DIABATICALLY
ENHANCED...LAID OUT SOMEWHERE IN THE CENTRAL IL TO NORTHERN IL
REGION. THE ONLY THING IS WITH SHORT WAVE RIDGING HINTED AT THIS
FEATURE APPEARS TO BE FAIRLY BENIGN...BUT SOMETHING TO KEEP AN
EYE ON.
MIDWEEK...AN ACTIVE PERIOD HERE AS PROLONGED SURFACE CYCLOGENESIS
BEGINS OVER THE SOUTHERN PLAINS MONDAY NIGHT AND CONTINUES THROUGH
TUESDAY WITH THE SURFACE WAVE ADVANCING ENE ON WED. MODEL
GUIDANCE HAS COME INTO BETTER AGREEMENT WITH THIS...LATCHING MORE
ONTO AN EC SOUTHERN SOLUTION. HAVE CONTINUED TO LEAN THAT WAY WITH
THE FORECAST WHICH MEANS INHIBITING TEMPERATURES ON WHAT COULD BE
GIVEN 850MB TEMPERATURES CLIMBING TO 8C-12C...ESPECIALLY NORTH OF
I-80. WITH FLOW OFF THE LAKE TUESDAY AND WEDNESDAY DUE TO THE LOW
BEING SOUTHWEST OF THE AREA...TEMPERATURES NEAR THE LAKE WILL
REMAIN COOLER. ALSO THIS FORECAST PATTERN MEANS LIKELY SEVERAL
BOUTS OF PRECIP WITH THE PROXIMITY OF THE ELEVATED WARM/STATIONARY
FRONT. THE 06.12 GFS AND EC RUNS BOTH HAVE OVER TWO AND A HALF
INCHES OF RAIN FORECAST AREA WIDE FROM SUNDAY NIGHT THROUGH
THURSDAY. WHILE IT IS CHALLENGING TO FOCUS ANY WINDOW FOR
CATEGORICAL POPS...IT WOULD SEEM WEDNESDAY AND WEDNESDAY NIGHT
WOULD BE THE MOST FAVORED PERIODS FOR STRONGER DYNAMIC FORCING AND
POSSIBLY MORE ROBUST ELEVATED CONVECTION WITH THE LARGE SCALE
UPPER TROUGH MOVING EASTWARD. COOLING BEHIND THE FRONT LOOKS
SOMEWHAT STRONG AND THERE IS A POTENTIAL TO SEE SOME MIX IN THE
WAKE OF THE FRONT...BUT CONFIDENCE IS VERY LOW ON HOW THIS SYSTEM
WILL EVOLVE AS IT LIFTS OUT.
BEYOND...HAVE GONE PRIMARILY WITH A MODEL CONSENSUS AT THE END OF
NEXT WEEK AS THE UPPER FLOW PATTERN WORKS FROM BRIEFLY NORTHWEST
BACK TO WEST. TEMPERATURES SHOULD GRADUALLY MODERATE BUT
CONFIDENCE IS LOW ON PRECIP CHANCES AS THE PATTERN STILL LOOKS
DISTURBED.
MTF
&&
.FIRE WEATHER...
328 AM...EASTERLY FLOW HAS MAINTAINED MUCH DRIER AIR ACROSS THE
REGION AND EXPECT A SLOW RETURN OF LOW LEVEL MOISTURE ACROSS THE
AREA TODAY. IT APPEARS DEWPOINTS WILL INCREASE BACK INTO THE
40S...BUT PROBABLY NOT UNTIL LATE AFTERNOON ACROSS WESTERN IL AND
THE REST OF THE AREA THIS EVENING. THUS MINIMUM RH VALUES TODAY
WILL LIKELY BE IN THE 35-40 PERCENT RANGE AND COULD POSSIBLY DIP
INTO THE 30-35 PERCENT RANGE. WHILE THESE EXPECTED VALUES WILL
REMAIN ABOVE RED FLAG CRITERIA OF 25 PERCENT...SOUTHERLY WINDS ARE
EXPECTED TO QUICKLY INCREASE THIS MORNING WITH GUSTS AS HIGH AS 40
MPH FROM LATE MORNING THROUGH SUNSET WITH THE POTENTIAL FOR HIGHER
GUSTS. WHILE THERE COULD BE A FEW LIGHT SHOWERS OR SPRINKLES
TODAY...THE BEST TIMING FOR SHOWERS AND A FEW THUNDERSTORMS WILL
BE FROM LATE AFTERNOON THROUGH MID/LATE EVENING. TEN HOUR FUEL
MOISTURE DIPPED TO 8-9 PERCENT ON FRIDAY AND SIMILAR VALUES ARE
POSSIBLE TODAY. AS A RESULT...THERE WILL BE AN INCREASED FIRE
DANGER AND WHILE MEETING RED FLAG CRITERIA IS NOT EXPECTED...
CONDITIONS WILL NEED TO BE MONITORED THROUGH DAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY SOUTH WINDS THROUGH THIS AFTN. GUSTS BETWEEN 35-40KT.
* WINDS SLOWLY TURN SOUTHWEST THIS EVENING...THEN BECOME NORTH TO
NORTHEAST EARLY SUN MORNING.
* CHANCE OF RAIN SHOWERS AROUND SUNSET THROUGH THE LATE EVENING
HOURS. ISOLATED CHANCE FOR THUNDER AS WELL.
BEACHLER
//DISCUSSION...UPDATED 18Z...
AN AREA OF LOW PRESSURE LOCATED ACROSS EASTERN NEBRASKA WILL
CONTINUE TO LIFT NORTHEAST TOWARDS CENTRAL WISCONSIN TONIGHT.
AHEAD OF THIS SYSTEM...THE GRADIENT HAS TIGHTENED. THE COMBINATION
OF A TIGHT PRESSURE GRADIENT AND WARMTH AT THE SFC HAS ALLOWED
GUSTY SFC WINDS FROM THE SOUTH. GUSTS UP TO 35 KT HAVE BEEN
OBSERVED EARLY THIS AFTERNOON...AND IT APPEARS THIS WILL CONTINUE
THROUGH EARLY THIS EVENING BEFORE MARGINALLY DIMINISHING TO AROUND
25 TO 30KT. THE OTHER CHALLENGE FOR AVIATION PURPOSES IS IN
REGARDS TO THE TIMING OF PRECIP. GUIDANCE HAS STEADILY BACKED OFF
ON PRECIP TRENDS...NOW FOCUSED ON A 02-05Z ARRIVAL TIME FOR
ORD/MDW. FOR RFD IT APPEARS ARND 00Z FOR THE INITIAL MENTION OF
PRECIP LOOKS PROBABLE. THE ENVIRONMENT DOES BECOME UNSTABLE...AND
COULD ALLOW FOR AN ISOLATED THUNDERSTORMS THIS EVENING ALTHOUGH
CONFIDENCE HAS DIMINISHED BASED ON TIMING. IN ADDITION TO THE
POSSIBILITY OF PRECIPITATION AND THUNDER...CLOUDS WILL STEADILY
LOWER. AT THIS TIME IT APPEARS THE LOWEST CLOUDS WILL PROBABLY
TOUCH MVFR CONDS FOR A BRIEF PERIOD OVERNIGHT. AT THIS TIME THE
THINKING IS THAT CIGS WILL REDUCE TO ARND 3KFT AGL.
THE FRONTAL BOUNDARY WILL STEADILY APPROACH THE REGION THIS
EVENING...AND ALLOW WINDS TO SLOWLY TURN WESTERLY ACROSS NORTHERN
IL/NORTHWEST IN AIRFIELDS. DRIER AIR WILL STEADILY SLIDE EAST
ACROSS THE REGION...THIS ALLOW CLOUDS TO SLOWLY ERODE BY SUN LATE
MORNING. WINDS ARE ALSO EXPECTED TO STEADILY TURN NORTH THEN
NORTHEASTERLY BY MIDDAY SUN...HOWEVER SPEEDS WILL BE MUCH LIGHTER
WITH UP TO 10 KT EXPECTED.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS THROUGH 06Z.
* MEDIUM CONFIDENCE IN TIMING OF PRECIP.
* LOW CONFIDENCE IN THUNDER IMPACTING ORD/MDW.
* MEDIUM CONFIDENCE IN WIND SHIFT EARLY SUN AND TIMING OF WINDS
TURNING NORTHEAST.
* MEDIUM CONFIDENCE IN CEILINGS FORECAST.
* LOW CONFIDENCE IN CIGS TOUCHING MVFR CONDS.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...SHRA/TSRA LIKELY LATE. MVFR PROBABLE SOME CHANCE OF
BRIEF IFR LATE.
MONDAY...SHRA/TSRA LIKELY EARLY. MVFR/BRIEF IFR POSSIBLE EARLY.
TUESDAY THROUGH THURSDAY NIGHT...PERIODIC CHANCE FOR SHRA/TSRA.
PERIODIC MVFR CIGS/VSBY LIKELY WITH BRIEF IFR POSSIBLE.
FRIDAY...PROBABLE VFR.
IZZI
&&
.MARINE...
241 PM CDT
LOW PRESSURE OVER SOUTHERN MINNESOTA THIS AFTERNOON IS LIFTING A
STRONG WARM FRONT ACROSS LAKE MICHIGAN TODAY. WINDS OVER THE LAND
ARE TOPPING OUT AROUND 35 KT THIS AFTERNOON WITH THESE GALES
EXTENDING INTO THE NEARSHORE WATERS WHERE A GALE WARNING REMAINS
IN EFFECT THROUGH THIS EVENING. HOWEVER...WITH TEMPERATURES
PUSHING 70 ACROSS NORTHERN ILLINOIS/INDIANA...VERY STABLE
CONDITIONS ARE SETTING UP OVER THE OPEN WATERS OF THE LAKE AND
SHOULD BE INHIBITING THE STRONGER GUSTS FROM REACHING THE LAKE
SURFACE. THE LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATE
THIS EVENING WITH A TRAILING COLD FRONT PUSHING ACROSS THE LAKE
SHORTLY THEREAFTER WITH WINDS TURNING WESTERLY AND DIMINISHING.
ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO MOVE INTO THE REGION
MIDWEEK...THOUGH MODELS CONTINUE TO STRUGGLE WITH TRACK AND TIMING
MAKING IT DIFFICULT TO PIN DOWN DETAILS REGARDING OVER THE LAKE.
CONTINUE TO FAVOR A FARTHER SOUTH SOLUTION SUPPORTED BY THE
CONSISTENT ECMWF...WHICH THE LATEST GFS HAS TRENDED TOWARDS.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...NEARSHORE WATERS UNTIL
10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1015 PM EDT SUN APR 7 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT SUN APR 7 2013
A BROAD DIFFUSE FRONTAL BOUNDARY WILL LIFT BACK NORTHWARD ACROSS
THE AREA TONIGHT AS A LOW PRESSURE SYSTEM MOVES INTO THE LOWER
GREAT LAKES. THIS WILL BRING SHOWER AND ISOLATED THUNDERSTORM
CHANCES TO THE AREA...WITH CHANCES FOR SHOWERS AND STORMS
REMAINING IN THE FORECAST THROUGH MUCH OF THE WEEK AS THE BOUNDARY
FLUCTUATES ACROSS THE REGION AND NUMEROUS DISTURBANCES MOVE ALONG
IT. THE STRONGEST OF THESE WILL COME TUESDAY NIGHT INTO WEDNESDAY
NIGHT AS A STRONGER LOW WILL FINALLY MOVE THROUGH THE
REGION...WITH THE OPPORTUNITY FOR WIDESPREAD THUNDERSTORMS. BEHIND
THIS SYSTEM...WEATHER WILL QUIET DOWN AND BECOME COOLER GOING INTO
THE WEEKEND.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 925 PM EDT SUN APR 7 2013
AREA OF SCATTERED SHOWERS/THUNDERSTORMS CONTINUES OVER THE FAR
SOUTHERN ZONES NEAR FRONTAL BOUNDARY. SURFACE WIND ALREADY VEERING
AROUND TO THE SOUTHEAST OVER EASTERN ILLINOIS...SO FRONT SHOULD
BEGIN PUSHING BACK NORTH OVER THE NEXT FEW HOURS. MODELS INDICATE A
40-45KT LOW LEVEL JET WILL DEVELOP DURING THE PRE DAWN HOURS OF
MONDAY...NOSING TOWARDS CENTRAL ILLINOIS/NORTHWEST INDIANA.
EXPECTING LITTLE CHANGE IN COVERAGE/INTENSITY OF CURRENT ACTIVITY AS
IT DRIFTS NORTH UNTIL AFTER 080600Z...WHERE ACTIVITY SHOULD BECOME
MORE WIDESPREAD AS LIFT INCREASES ALONG THE INTENSIFYING LOW LEVEL
JET. WILL INCREASE POPS INTO THE LIKELY CATEGORY OVER ALL BUT THE
FAR EASTERN/SOUTHEASTERN ZONES AFTER 080600Z.
TEMPERATURES RUNNING WARMER THAN WHAT WAS EXPECTED BY THIS
TIME...BUT TEMPERATURES SHOULD COOL TO NEAR WET BULBS LATER TONIGHT
WITH EXPECTED SHOWER ACTIVITY...WHICH IS CLOSE TO FORECAST LOWS.
PREVIOUS DISCUSSION FOLLOWS.
FRONTAL BOUNDARY ACROSS THE AREA IS VERY BROAD...WITH DEWPOINTS
POOLING SOUTH AND WIND SHIFT ACROSS THE NORTH. HAVE LEANED MORE
TOWARD NAM SOLUTION AS GFS HAS BEEN VERY AGGRESSIVE DEVELOPING
PRECIP TODAY WHERE NONE SO FAR HAS OCCURRED.
THIS BOUNDARY WILL GRADUALLY MOVE NORTHWARD AS A WEAK SURFACE LOW
MOVES INTO THE REGION. SHOWERS AND A FEW THUNDERSTORMS SHOULD
RESULT...BUT PERHAPS NOT QUITE AS MUCH AS SOME OF THE GUIDANCE
WISHES TO DEVELOP. WILL CUT DOWN ON POPS MORE INTO THE LOW TO MID
CHANCE CATEGORY...SAVE FOR THE FAR NORTHWEST LATE...NEARER THE
BOUNDARY AND SURFACE LOW POSITION AT THAT TIME.
ON TEMPS...UPSTREAM TEMPS AND THICKNESSES SUGGEST LOW TO MID
50S...AND CONSENSUS AGREES WITH THIS RELATIVELY WELL.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 340 PM EDT SUN APR 7 2013
BOUNDARY REMAINS IN THE REGION THROUGHOUT THE PERIOD...MAINLY TO
THE NORTH...WHICH SHOULD ALLOW CONTINUED WARMTH BUT ALSO NEARLY
CONTINUOUS CHANCES FOR THUNDERSTORMS. THAT SAID...HAVE CONTINUED
TO CUT BACK ON POPS A BIT FROM WHAT GUIDANCE PROVIDED AS UPPER
SUPPORT IS OFTEN LACKING AND FORECAST SOUNDINGS INDICATE A
DEVELOPING MIDLEVEL INVERSION LATE MONDAY INTO TUESDAY
NIGHT...BECOMING QUITE STRONG AT TIMES.
ON TEMPS...CLOUD COVER WILL INTRODUCE SIGNIFICANT UNCERTAINTY INTO
THIS PORTION OF THE FORECAST. ANY SUN BREAKING THROUGH COULD ALLOW
TEMPS TO PUSH WELL INTO THE 70S EACH DAY...BUT WITH AMPLE CLOUD
COVER EXPECTED AT THIS TIME...HAVE CUT BACK SLIGHTLY ON GUIDANCE
NUMBERS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 233 PM EDT SUN APR 7 2013
APPEARS THE BEST CHANCES FOR ANY ORGANIZED THUNDERSTORM DEVELOPMENT
ACROSS CENTRAL INDIANA WILL HAVE TO BE WITH THE LOW TRACKING ACROSS
THE UPPER MIDWEST WED AND WED NIGHT...AT THE VERY BEGINNING OF THE
EXTENDED PERIOD. SEVERE WX INDICES INDICATE THESE THUNDERSTORMS
COULD BE STRONG AND CONTAIN VERY HEAVY RAIN BASED ON PWATS AND QPF
AMOUNTS. SHOWERS WILL THEN REMAIN IN THE FORECAST THROUGH EARLY
FRIDAY...THEN THE AREA GETS A BRIEF RESPITE FROM PRECIP EARLY THIS
WEEKEND. RAIN CHANCES WILL THEN RESUME LATE SUNDAY. CONSALL TEMPS
LOOK REASONABLE FOR MOST PART SO DID NOT STRAY FAR FROM
INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR 080300Z TAF ISSUANCE/...
ISSUED AT 1015 PM EDT SUN APR 7 2013
WARM FRONT AND ASSOCIATED CONVECTION CONTINUING TO SHIFT NORTH
SLOWLY ACROSS SOUTHERN FORECAST AREA THIS EVENING. BACKED OFF ON
VCSH BY AN HOUR OR SO AT KHUF/KIND/LAF BASED ON CURRENT OBS/TRENDS.
ALSO ENDED PRECIP A FEW HOURS QUICKER IN THE MORNING BASED ON NEWEST
SHORT RANGE MODEL GUIDANCE. WINDS ARE IN THE PROCESS OF SHIFTING TO
A SE DIRECTION AS LOW PRESSURE CURRENTLY MOVES INTO WESTERN
MISSOURI.
00Z DISCUSSION FOLLOWS.
MAINLY VFR CONDITIONS TONIGHT...MVFR CONDITIONS DEVELOPING LATE
TONIGHT AND MONDAY MORNING WITHIN CONVECTION.
WARM FRONT CURRENTLY LOCATED ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA THIS EVENING...WITH A BROKEN CONVECTIVE LINE JUST
SOUTH OF THE BOUNDARY. THE FRONT WILL SHIFT NORTH ACROSS THE
FORECAST AREA TONIGHT IN RESPONSE TO LOW PRESSURE TRACKING OUT OF
THE CENTRAL PLAINS. MOST RECENT HRRR SUGGESTING THAT BROKEN LINE
OF SHOWERS AND EMBEDDED THUNDERSTORMS WILL FOLLOW THE BOUNDARY
NORTH OVER THE NEXT SEVERAL HOURS...WITH POTENTIAL FOR MORE
WIDESPREAD CONVECTION INTO THE AREA AFTER 06Z AS A LOW LEVEL JET
ORGANIZES AHEAD OF THE APPROACHING SURFACE LOW. INITIAL IMPACTS
FOR KBMG THIS EVENING WITH SCATTERED CONVECTION IN THE AREA...
SPREADING NORTH TO KHUF AND KIND BY 04-06Z...AND FINALLY TO KLAF
AFTER 06Z. AXIS OF ELEVATED INSTABILITY ACCOMPANIES THE BOUNDARY
NORTH AND WILL SUPPORT AT LEAST THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM OVERNIGHT AT ALL TERMINALS...WITH GREATEST POTENTIAL
FOR THUNDER AT KLAF IN CLOSEST PROXIMITY TO THE TRACK OF THE LOW.
LIKELY TO EXPERIENCE MVFR CONDITIONS LATE WITHIN CONVECTION.
MODELS SHIFT THE FRONT AND WIDESPREAD PRECIP NORTH OF ALL
TERMINALS MONDAY MORNING. ABUNDANT LOW LEVEL MOISTURE REMAINS
HOWEVER WHICH SHOULD SERVE TO MAINTAIN AN MVFR STRATOCU DECK INTO
EARLY AFTERNOON. INCREASED MIXING WILL HELP TO LIFT OUT STRATOCU
TO A VFR CU FIELD FOR THE AFTERNOON. COULD SEE SCATTERED
CONVECTION AGAIN DURING THE AFTERNOON...BUT COVERAGE LOOKS TO BE
TOO LOW TO MENTION AT THIS TIME. SOUTHWEST WINDS WILL GUST TO
25-30KTS FROM MID MORNING ON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD/JAS
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
925 PM EDT SUN APR 7 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT SUN APR 7 2013
A BROAD DIFFUSE FRONTAL BOUNDARY WILL LIFT BACK NORTHWARD ACROSS
THE AREA TONIGHT AS A LOW PRESSURE SYSTEM MOVES INTO THE LOWER
GREAT LAKES. THIS WILL BRING SHOWER AND ISOLATED THUNDERSTORM
CHANCES TO THE AREA...WITH CHANCES FOR SHOWERS AND STORMS
REMAINING IN THE FORECAST THROUGH MUCH OF THE WEEK AS THE BOUNDARY
FLUCTUATES ACROSS THE REGION AND NUMEROUS DISTURBANCES MOVE ALONG
IT. THE STRONGEST OF THESE WILL COME TUESDAY NIGHT INTO WEDNESDAY
NIGHT AS A STRONGER LOW WILL FINALLY MOVE THROUGH THE
REGION...WITH THE OPPORTUNITY FOR WIDESPREAD THUNDERSTORMS. BEHIND
THIS SYSTEM...WEATHER WILL QUIET DOWN AND BECOME COOLER GOING INTO
THE WEEKEND.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 925 PM EDT SUN APR 7 2013
AREA OF SCATTERED SHOWERS/THUNDERSTORMS CONTINUES OVER THE FAR
SOUTHERN ZONES NEAR FRONTAL BOUNDARY. SURFACE WIND ALREADY VEERING
AROUND TO THE SOUTHEAST OVER EASTERN ILLINOIS...SO FRONT SHOULD
BEGIN PUSHING BACK NORTH OVER THE NEXT FEW HOURS. MODELS INDICATE A
40-45KT LOW LEVEL JET WILL DEVELOP DURING THE PRE DAWN HOURS OF
MONDAY...NOSING TOWARDS CENTRAL ILLINOIS/NORTHWEST INDIANA.
EXPECTING LITTLE CHANGE IN COVERAGE/INTENSITY OF CURRENT ACTIVITY AS
IT DRIFTS NORTH UNTIL AFTER 080600Z...WHERE ACTIVITY SHOULD BECOME
MORE WIDESPREAD AS LIFT INCREASES ALONG THE INTENSIFYING LOW LEVEL
JET. WILL INCREASE POPS INTO THE LIKELY CATEGORY OVER ALL BUT THE
FAR EASTERN/SOUTHEASTERN ZONES AFTER 080600Z.
TEMPERATURES RUNNING WARMER THAN WHAT WAS EXPECTED BY THIS
TIME...BUT TEMPERATURES SHOULD COOL TO NEAR WET BULBS LATER TONIGHT
WITH EXPECTED SHOWER ACTIVITY...WHICH IS CLOSE TO FORECAST LOWS.
PREVIOUS DISCUSSION FOLLOWS.
FRONTAL BOUNDARY ACROSS THE AREA IS VERY BROAD...WITH DEWPOINTS
POOLING SOUTH AND WIND SHIFT ACROSS THE NORTH. HAVE LEANED MORE
TOWARD NAM SOLUTION AS GFS HAS BEEN VERY AGGRESSIVE DEVELOPING
PRECIP TODAY WHERE NONE SO FAR HAS OCCURRED.
THIS BOUNDARY WILL GRADUALLY MOVE NORTHWARD AS A WEAK SURFACE LOW
MOVES INTO THE REGION. SHOWERS AND A FEW THUNDERSTORMS SHOULD
RESULT...BUT PERHAPS NOT QUITE AS MUCH AS SOME OF THE GUIDANCE
WISHES TO DEVELOP. WILL CUT DOWN ON POPS MORE INTO THE LOW TO MID
CHANCE CATEGORY...SAVE FOR THE FAR NORTHWEST LATE...NEARER THE
BOUNDARY AND SURFACE LOW POSITION AT THAT TIME.
ON TEMPS...UPSTREAM TEMPS AND THICKNESSES SUGGEST LOW TO MID
50S...AND CONSENSUS AGREES WITH THIS RELATIVELY WELL.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 340 PM EDT SUN APR 7 2013
BOUNDARY REMAINS IN THE REGION THROUGHOUT THE PERIOD...MAINLY TO
THE NORTH...WHICH SHOULD ALLOW CONTINUED WARMTH BUT ALSO NEARLY
CONTINUOUS CHANCES FOR THUNDERSTORMS. THAT SAID...HAVE CONTINUED
TO CUT BACK ON POPS A BIT FROM WHAT GUIDANCE PROVIDED AS UPPER
SUPPORT IS OFTEN LACKING AND FORECAST SOUNDINGS INDICATE A
DEVELOPING MIDLEVEL INVERSION LATE MONDAY INTO TUESDAY
NIGHT...BECOMING QUITE STRONG AT TIMES.
ON TEMPS...CLOUD COVER WILL INTRODUCE SIGNIFICANT UNCERTAINTY INTO
THIS PORTION OF THE FORECAST. ANY SUN BREAKING THROUGH COULD ALLOW
TEMPS TO PUSH WELL INTO THE 70S EACH DAY...BUT WITH AMPLE CLOUD
COVER EXPECTED AT THIS TIME...HAVE CUT BACK SLIGHTLY ON GUIDANCE
NUMBERS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 233 PM EDT SUN APR 7 2013
APPEARS THE BEST CHANCES FOR ANY ORGANIZED THUNDERSTORM DEVELOPMENT
ACROSS CENTRAL INDIANA WILL HAVE TO BE WITH THE LOW TRACKING ACROSS
THE UPPER MIDWEST WED AND WED NIGHT...AT THE VERY BEGINNING OF THE
EXTENDED PERIOD. SEVERE WX INDICES INDICATE THESE THUNDERSTORMS
COULD BE STRONG AND CONTAIN VERY HEAVY RAIN BASED ON PWATS AND QPF
AMOUNTS. SHOWERS WILL THEN REMAIN IN THE FORECAST THROUGH EARLY
FRIDAY...THEN THE AREA GETS A BRIEF RESPITE FROM PRECIP EARLY THIS
WEEKEND. RAIN CHANCES WILL THEN RESUME LATE SUNDAY. CONSALL TEMPS
LOOK REASONABLE FOR MOST PART SO DID NOT STRAY FAR FROM
INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR 080000Z TAF ISSUANCE/...
ISSUED AT 726 PM EDT SUN APR 7 2013
MAINLY VFR CONDITIONS TONIGHT...MVFR CONDITIONS DEVELOPING LATE
TONIGHT AND MONDAY MORNING WITHIN CONVECTION.
WARM FRONT CURRENTLY LOCATED ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA THIS EVENING...WITH A BROKEN CONVECTIVE LINE JUST
SOUTH OF THE BOUNDARY. THE FRONT WILL SHIFT NORTH ACROSS THE
FORECAST AREA TONIGHT IN RESPONSE TO LOW PRESSURE TRACKING OUT OF
THE CENTRAL PLAINS. MOST RECENT HRRR SUGGESTING THAT BROKEN LINE
OF SHOWERS AND EMBEDDED THUNDERSTORMS WILL FOLLOW THE BOUNDARY
NORTH OVER THE NEXT SEVERAL HOURS...WITH POTENTIAL FOR MORE
WIDESPREAD CONVECTION INTO THE AREA AFTER 06Z AS A LOW LEVEL JET
ORGANIZES AHEAD OF THE APPROACHING SURFACE LOW. INITIAL IMPACTS
FOR KBMG THIS EVENING WITH SCATTERED CONVECTION IN THE AREA...
SPREADING NORTH TO KHUF AND KIND BY 04-06Z...AND FINALLY TO KLAF
AFTER 06Z. AXIS OF ELEVATED INSTABILITY ACCOMPANIES THE BOUNDARY
NORTH AND WILL SUPPORT AT LEAST THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM OVERNIGHT AT ALL TERMINALS...WITH GREATEST POTENTIAL
FOR THUNDER AT KLAF IN CLOSEST PROXIMITY TO THE TRACK OF THE LOW.
LIKELY TO EXPERIENCE MVFR CONDITIONS LATE WITHIN CONVECTION.
MODELS SHIFT THE FRONT AND WIDESPREAD PRECIP NORTH OF ALL
TERMINALS MONDAY MORNING. ABUNDANT LOW LEVEL MOISTURE REMAINS
HOWEVER WHICH SHOULD SERVE TO MAINTAIN AN MVFR STRATOCU DECK INTO
EARLY AFTERNOON. INCREASED MIXING WILL HELP TO LIFT OUT STRATOCU
TO A VFR CU FIELD FOR THE AFTERNOON. COULD SEE SCATTERED
CONVECTION AGAIN DURING THE AFTERNOON...BUT COVERAGE LOOKS TO BE
TOO LOW TO MENTION AT THIS TIME. SOUTHWEST WINDS WILL GUST TO
25-30KTS FROM MID MORNING ON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD/JAS
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
726 PM EDT SUN APR 7 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT SUN APR 7 2013
A BROAD DIFFUSE FRONTAL BOUNDARY WILL LIFT BACK NORTHWARD ACROSS
THE AREA TONIGHT AS A LOW PRESSURE SYSTEM MOVES INTO THE LOWER
GREAT LAKES. THIS WILL BRING SHOWER AND ISOLATED THUNDERSTORM
CHANCES TO THE AREA...WITH CHANCES FOR SHOWERS AND STORMS
REMAINING IN THE FORECAST THROUGH MUCH OF THE WEEK AS THE BOUNDARY
FLUCTUATES ACROSS THE REGION AND NUMEROUS DISTURBANCES MOVE ALONG
IT. THE STRONGEST OF THESE WILL COME TUESDAY NIGHT INTO WEDNESDAY
NIGHT AS A STRONGER LOW WILL FINALLY MOVE THROUGH THE
REGION...WITH THE OPPORTUNITY FOR WIDESPREAD THUNDERSTORMS. BEHIND
THIS SYSTEM...WEATHER WILL QUIET DOWN AND BECOME COOLER GOING INTO
THE WEEKEND.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 340 PM EDT SUN APR 7 2013
FRONTAL BOUNDARY ACROSS THE AREA IS VERY BROAD...WITH DEWPOINTS
POOLING SOUTH AND WIND SHIFT ACROSS THE NORTH. HAVE LEANED MORE
TOWARD NAM SOLUTION AS GFS HAS BEEN VERY AGGRESSIVE DEVELOPING
PRECIP TODAY WHERE NONE SO FAR HAS OCCURRED.
THIS BOUNDARY WILL GRADUALLY MOVE NORTHWARD AS A WEAK SURFACE LOW
MOVES INTO THE REGION. SHOWERS AND A FEW THUNDERSTORMS SHOULD
RESULT...BUT PERHAPS NOT QUITE AS MUCH AS SOME OF THE GUIDANCE
WISHES TO DEVELOP. WILL CUT DOWN ON POPS MORE INTO THE LOW TO MID
CHANCE CATEGORY...SAVE FOR THE FAR NORTHWEST LATE...NEARER THE
BOUNDARY AND SURFACE LOW POSITION AT THAT TIME.
ON TEMPS...UPSTREAM TEMPS AND THICKNESSES SUGGEST LOW TO MID
50S...AND CONSENSUS AGREES WITH THIS RELATIVELY WELL.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 340 PM EDT SUN APR 7 2013
BOUNDARY REMAINS IN THE REGION THROUGHOUT THE PERIOD...MAINLY TO
THE NORTH...WHICH SHOULD ALLOW CONTINUED WARMTH BUT ALSO NEARLY
CONTINUOUS CHANCES FOR THUNDERSTORMS. THAT SAID...HAVE CONTINUED
TO CUT BACK ON POPS A BIT FROM WHAT GUIDANCE PROVIDED AS UPPER
SUPPORT IS OFTEN LACKING AND FORECAST SOUNDINGS INDICATE A
DEVELOPING MIDLEVEL INVERSION LATE MONDAY INTO TUESDAY
NIGHT...BECOMING QUITE STRONG AT TIMES.
ON TEMPS...CLOUD COVER WILL INTRODUCE SIGNIFICANT UNCERTAINTY INTO
THIS PORTION OF THE FORECAST. ANY SUN BREAKING THROUGH COULD ALLOW
TEMPS TO PUSH WELL INTO THE 70S EACH DAY...BUT WITH AMPLE CLOUD
COVER EXPECTED AT THIS TIME...HAVE CUT BACK SLIGHTLY ON GUIDANCE
NUMBERS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 233 PM EDT SUN APR 7 2013
APPEARS THE BEST CHANCES FOR ANY ORGANIZED THUNDERSTORM DEVELOPMENT
ACROSS CENTRAL INDIANA WILL HAVE TO BE WITH THE LOW TRACKING ACROSS
THE UPPER MIDWEST WED AND WED NIGHT...AT THE VERY BEGINNING OF THE
EXTENDED PERIOD. SEVERE WX INDICES INDICATE THESE THUNDERSTORMS
COULD BE STRONG AND CONTAIN VERY HEAVY RAIN BASED ON PWATS AND QPF
AMOUNTS. SHOWERS WILL THEN REMAIN IN THE FORECAST THROUGH EARLY
FRIDAY...THEN THE AREA GETS A BRIEF RESPITE FROM PRECIP EARLY THIS
WEEKEND. RAIN CHANCES WILL THEN RESUME LATE SUNDAY. CONSALL TEMPS
LOOK REASONABLE FOR MOST PART SO DID NOT STRAY FAR FROM
INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR 080000Z TAF ISSUANCE/...
ISSUED AT 726 PM EDT SUN APR 7 2013
MAINLY VFR CONDITIONS TONIGHT...MVFR CONDITIONS DEVELOPING LATE
TONIGHT AND MONDAY MORNING WITHIN CONVECTION.
WARM FRONT CURRENTLY LOCATED ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA THIS EVENING...WITH A BROKEN CONVECTIVE LINE JUST
SOUTH OF THE BOUNDARY. THE FRONT WILL SHIFT NORTH ACROSS THE
FORECAST AREA TONIGHT IN RESPONSE TO LOW PRESSURE TRACKING OUT OF
THE CENTRAL PLAINS. MOST RECENT HRRR SUGGESTING THAT BROKEN LINE
OF SHOWERS AND EMBEDDED THUNDERSTORMS WILL FOLLOW THE BOUNDARY
NORTH OVER THE NEXT SEVERAL HOURS...WITH POTENTIAL FOR MORE
WIDESPREAD CONVECTION INTO THE AREA AFTER 06Z AS A LOW LEVEL JET
ORGANIZES AHEAD OF THE APPROACHING SURFACE LOW. INITIAL IMPACTS
FOR KBMG THIS EVENING WITH SCATTERED CONVECTION IN THE AREA...
SPREADING NORTH TO KHUF AND KIND BY 04-06Z...AND FINALLY TO KLAF
AFTER 06Z. AXIS OF ELEVATED INSTABILITY ACCOMPANIES THE BOUNDARY
NORTH AND WILL SUPPORT AT LEAST THE POTENTIAL FOR AN ISOLATED
THUNDERSTORM OVERNIGHT AT ALL TERMINALS...WITH GREATEST POTENTIAL
FOR THUNDER AT KLAF IN CLOSEST PROXIMITY TO THE TRACK OF THE LOW.
LIKELY TO EXPERIENCE MVFR CONDITIONS LATE WITHIN CONVECTION.
MODELS SHIFT THE FRONT AND WIDESPREAD PRECIP NORTH OF ALL
TERMINALS MONDAY MORNING. ABUNDANT LOW LEVEL MOISTURE REMAINS
HOWEVER WHICH SHOULD SERVE TO MAINTAIN AN MVFR STRATOCU DECK INTO
EARLY AFTERNOON. INCREASED MIXING WILL HELP TO LIFT OUT STRATOCU
TO A VFR CU FIELD FOR THE AFTERNOON. COULD SEE SCATTERED
CONVECTION AGAIN DURING THE AFTERNOON...BUT COVERAGE LOOKS TO BE
TOO LOW TO MENTION AT THIS TIME. SOUTHWEST WINDS WILL GUST TO
25-30KTS FROM MID MORNING ON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1234 AM CDT SAT APR 6 2013
.UPDATE...
ISSUED AT 940 PM CDT FRI APR 5 2013
LAKE MI ENHANCED BOUNDARY SLIPPING INTO EASTERN COUNTIES AND
LIKELY NOT GOING TO MAKE MUCH MORE PROGRESS INTO CWA BEFORE
WASHING OUT GIVEN EVOLVING PRESSURE FALLS AHEAD OF SOUTHERN
NEBRASKA SFC LOW AND TRAILING WARM FRONT THROUGH SOUTHEAST
MISSOURI. STILL... EXPECT FAIRLY LARGE TEMP GRADIENT ON LOWS
TNGT WITH AREAS IN NORTHWEST ILLINOIS BEHIND LAKE BOUNDARY
CHILLED INTO THE 30S WHILE AREAS IN SOUTHEAST IOWA...NORTHEAST
MISSOURI HOLDING UP AROUND 50 DEGS. ANY PCPN CHCS OVERNIGHT WILL
HINGE ON INCREASING 50 KT LOW LEVEL JET WHICH IS SHOWN TO VEER
INTO CWA LATE TONIGHT AND SATURDAY MORNING. DESPITE THIS LIFT
HOWEVER... THERE IS PLENTY OF CONCERN WITH VERY DRY AIRMASS
AT 850 MB TO OUR SOUTH THIS EVE PER 00Z RAOB ANALYSIS. THIS WILL
ADVECT NORTHWARD AND WHILE WE MAY SEE SOME HIGH BASED RETURNS
DEVELOPING OVERNIGHT LOTS OF DRY AIR BELOW 800 MB PUTS SERIOUS
QUESTIONS ON WHETHER ANYTHING WILL BE ABLE TO REACH THE GROUND.
AS RESULT... HAVE BEGUN TO TRIM BACK PCPN CHCS REST OF TONIGHT.
&&
.SYNOPSIS...
ISSUED AT 109 PM CDT FRI APR 5 2013
12Z UA ANALYSIS HAS AN 850MB COLD FRONT FROM THE MID ATLANTIC STATES
INTO SOUTHEAST IOWA. A RIDGE RAN FROM SOUTHERN TEXAS TO LAKE
WINNIPEG IN CANADA AND A LLJ RAN FROM WEST TEXAS INTO WESTERN
NEBRASKA. SATELLITE TRENDS THROUGH MID DAY SHOW INCREASING MID AND
HIGH LEVEL CLOUDS ACROSS THE MID MISSISSIPPI VALLEY.
18Z SFC ANALYSIS HAS A LOW ALONG THE NE/SD BORDER NEAR KIEN WITH A
WARM FRONT INTO SOUTH DAKOTA AND THEN DROPPING SOUTH ALONG THE
MISSOURI RIVER. THE MODIFIED ARCTIC FRONT WAS INTO THE TENNESSEE
VALLEY AND SOUTHERN MISSOURI. DEW POINTS OVER THE GREAT LAKES WERE
IN THE TEENS AND 20S WITH 30S AND 40S IN THE CENTRAL AND SOUTHERN
PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 109 PM CDT FRI APR 5 2013
THE DRY AIR IS HAMPERING THE DEVELOPMENT OF THE WAA PRECIPITATION
WING FROM MN INTO WISCONSIN. HOWEVER...RAP TRENDS WITH THE 850-700MB
CONDENSATION PRESSURE DEFICITS COMBINED WITH OVERALL
FORCING/CONVERGENCE AGREE QUITE NICELY WITH THE PRECIPITATION
APPROACHING THE MISSISSIPPI RIVER AROUND KMSP.
USING THIS AS A GUIDE THERE MAY BE SOME ISOLATED SHRA/SPRINKLES THAT
IMPINGE ALONG THE NORTHERN BORDER OF THE CWFA LATE THIS AFTERNOON
AND EARLY EVENING. ONCE THE FORCING SHIFTS NORTHEAST OF THE AREA BY
SUNSET...DRY CONDITIONS SHOULD THEN BE SEEN ACROSS THE AREA THROUGH
MIDNIGHT.
AFTER MIDNIGHT THINGS GET MORE INTERESTING.
THE MCS AND LIFT TOOLS ARE SUGGESTING CONVECTION DEVELOPING JUST
WEST OF I-35 IN THE STRENGTHENING LLJ BY MIDNIGHT. IF THE RAP TRENDS
ARE CORRECT THIS CONVECTION OF SHRA/TSRA SHOULD BE ON THE WESTERN
BORDER OF THE CWFA BY 09Z AND OVER THE WESTERN HALF OF THE CWFA BY
SUNRISE. THE COMBINATION OF THE LLJ AND STEEP MID LEVEL LAPSE RATES
SHOULD MAINTAIN THE CONVECTION AND ALSO RESULT IN WINDS INCREASING
DURING THE NIGHT.
THE ABOVE MENTIONED CONVECTION SHOULD EXIT THE CWFA BY LATE MORNING
AND THERE SHOULD BE A BRIEF PAUSE BEFORE NEW DIURNAL CONVECTION
DEVELOPS BY MID DAY AND CONTINUES THROUGH THE AFTERNOON HOURS.
LOW LEVEL LAPSE RATES BECOME QUITE STEEP AND THE WAA IS QUITE STRONG
ON SATURDAY WHICH WILL ALLOW THE HIGHER MOMENTUM AIR ALOFT TO MIX
DOWN. WINDS ARE EXPECTED TO PICK UP SIGNIFICANTLY BY LATE MORNING
AND CONTINUE THROUGH THE AFTERNOON.
THE SITUATION SATURDAY WILL NEED TO BE WATCHED CAREFULLY. THE
POTENTIAL DOES EXIST FOR A LOW END WIND ADVISORY FOR AREAS ALONG AND
EAST OF THE MISSISSIPPI FROM LATE MORNING THROUGH THE AFTERNOON
HOURS. ..08..
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 109 PM CDT FRI APR 5 2013
SATURDAY NIGHT AND SUNDAY SHOULD BE RELATIVELY QUIET AS A RIDGE OF
THE HIGH PRESSURE NOSES INTO THE REGION FROM THE NORTH. SOME LOW
CHANCE POPS WERE MAINTAINED EAST OF THE MISSISSIPPI RIVER SATURDAY
EVENING TO COVER ANY LINGERING SHOWERS BEHIND THE DEPARTING COLD
FRONT. BY SUNDAY MORNING THE COLD FRONT SHOULD BE STALLED OVER
CENTRAL OR NORTHERN MO WITH THE HIGH PRESSURE RIDGE OVER THE
NORTHERN CWFA. THIS SHOULD KEEP DRY WEATHER OVER MUCH OF THE AREA
THROUGH THE DAY SUNDAY. HOWEVER...KEPT SOME LOW POPS GOING IN THE
FAR SOUTH IN THE AFTERNOON WITH THE SURFACE FRONT JUST TO THE
SOUTH.
SUNDAY NIGHT A LOW AMPLITUDE S/W WILL MOVE THROUGH THE REGION
SPAWNING SHOWERS AND THUNDERSTORMS ALONG AND NORTH OF THE STALLED
FRONT. THE 00Z ECMWF WAS GENERATING SOME QPF WITH THIS FEATURE
OVER THE WESTERN CWFA AS EARLY AS SUNDAY AFTERNOON. BUT THE
FORCING SHOWN BY THE ECMWF WOULD SHOW MORE FAVORABLE CONDITIONS
OVER WESTERN IOWA BEFORE 00Z. OTHER THAN THE LOW CHANCE POPS IN
THE SOUTH SUNDAY AFTERNOON DISCUSSED ABOVE...THE SIGNIFICANT POPS
WERE LIMITED TO SUNDAY NIGHT WITH LIKELY/S OVER THEN ENTIRE AREA
WHEN AN AREA OF SHOWERS AND THUNDERSTORMS SHOULD MOVE EAST ACROSS
THE REGION AHEAD OF THE MID LEVEL SHORTWAVE. AT THIS POINT THE
SEVERE THUNDERSTORMS THREAT LOOKS NIL DUE LOW INSTABILITY AND
UNIMPRESSIVE FORCING. PW/S OVER THE AREA SUNDAY NIGHT ARE EXPECTED
TO BE AROUND AN INCH SUGGESTING GENERAL RAINFALL AMOUNTS OF A HALF
TO THREE QUARTERS OF AN INCH. THE HIGHER AMOUNTS WOULD FAVOR THE
SOUTH CLOSE TO THE SURFACE FRONT.
SHOWER AND THUNDERSTORM CHANCES WILL REMAIN OVER THE AREA MONDAY
THROUGH WEDNESDAY. THE LARGE TROF DEVELOPING OVER THE WESTERN U.S.
WILL CONTINUE TO FEED AMPLE MOISTURE INTO THE CENTRAL U.S. WHERE A
FRONTAL BOUNDARY WILL REMAIN. DURING THIS TIME FRAME...TUESDAY INTO
WEDNESDAY HAVE THE BEST CHANCE FOR SIGNIFICANT RAINS WHEN THE MODELS
SHOW A SURFACE LOW EJECTING NORTHEAST OUT OF THE SOUTHERN PLAINS
AHEAD OF THE UPPER TROF. EVEN THOUGH THIS FEATURE IS SHOWN BY ALL
MODELS THERE CONTINUES TO BE A VARIETY OF SOLUTIONS ON THE DETAILS
OF THE TRACK AND TIMING. THE 12Z ECMWF HAS SHIFTED THE TRACK
FURTHER SOUTHEAST SUGGESTING THE SIGNIFICANT RAINS WILL MISS THE
FORECAST AREA. THE GEM/GFS TRACK THE SYSTEM OVER IOWA TUESDAY OR
TUESDAY NIGHT SUPPORTING ANOTHER ROUND OF AT LEAST MODERATE RAINS.
GIVEN THE AMOUNT OF MOISTURE INPLACE AND A SURFACE BOUNDARY IN
THE AREA THE THREAT OF RAIN STILL LOOKS GOOD MONDAY THROUGH
WEDNESDAY WITH THE BIGGEST QUESTION NOW BEING THE RAINFALL
AMOUNTS. SO HAVE CONTINUED TO MENTION LIKELY POPS OVER MUCH OF THE
AREA FOR SHOWERS AND THUNDERSTORMS. THEN WEDNESDAY WHEN THE UPPER
TROF MOVES THROUGH...POPS WERE BACKED DOWN TO CHANCE CATEGORY.
COLDER AIR ADVECTING IN BEHIND THE TROF WEDNESDAY NIGHT COULD
PRODUCE A MIX OF RAIN AND SNOW ESPECIALLY NORTH. HOWEVER PRECIP
AMOUNTS SHOULD BE LIGHT MAKING IT UNLIKELY THAT ANY ACCUMULATION
WILL OCCUR. PRECIP COULD LINGER INTO THURSDAY AND THURSDAY NIGHT
WITH H8 TEMPS REMAINING BELOW ZERO. HOWEVER... TEMPERATURES NEAR
THE SURFACE SHOULD BE WARM ENOUGH FOR ALL RAIN.
DEEP SOUTHERLY FLOW AND HIGH MOISTURE LEVELS WILL KEEP
TEMPERATURES ON THE MILD SIDE EARLY NEXT WEEK...BUT BELOW NORMAL
READINGS WILL RETURN FOR THE END OF THE WEEK AS THE COLDER AIR
MOVES IN BEHIND THE DEPARTING UPPER TROF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1217 AM CDT SAT APR 6 2013
VFR CONDITIONS PREDOMINANT THROUGH MUCH IF NOT ALL OF TAF CYCLE.
LOW PRESSURE OVER SOUTHERN NEBRASKA WILL MOVE EAST AND LIFT WARM
FRONT THROUGH THE TERMINALS SATURDAY MORNING. THERE IS A CHANCE
OF SCATTERED HIGH BASED SHOWERS AHEAD OF THE WARM FRONTAL PASSAGE
SATURDAY MORNING BUT CONSIDERABLE DRY AIR BELOW 12KFT AGL LENDS
LOW CONFIDENCE ON ANYTHING REACHING THE GROUND... BUT IF IT SHOULD
IT MOST LIKELY TO BE MAINLY SPRINKLES WITH VSBYS AOA 6SM. THEREFORE
HAVE LEFT OUT ANY MENTION OF PCPN IN THE MORNING... BUT HAVE
MAINTAINED VCSH WORDING FOR SATURDAY AFTERNOON INTO EARLY EVENING
WHERE BETTER CHANCES FOR SHOWERS AND EVEN ISOLATED THUNDERSTORMS
EXISTS AS A COLD FRONT AND UPPER LEVEL DISTURBANCE MOVE INTO THE
REGION. SOUTHEAST WINDS WILL CONTINUE TO INCREASE OVERNIGHT WITH
GUSTS AT TIMES TO 20-30 KTS... THIS AS A LOW LEVEL JET STRENGTHENS
TO 50+ KTS AROUND 5KFT AGL. RATHER WINDY CONDITIONS WILL PREVAIL
MUCH OF SATURDAY SUSTAINED AT 20 TO 26+ KTS WITH SOME GUSTS OF
32-36 KTS AT TIMES WHILE VEERING FROM SOUTHEAST TO SOUTHWEST.
WINDS TO DECREASE AND SHIFT TO WEST AND NORTHWEST AROUND 10-15 KTS
SATURDAY EVENING. THERE IS A CHANCE FOR MVFR CONDITIONS TO
DEVELOP MAINLY SATURDAY AFTERNOON INTO EVENING WITH THE COLD
FRONT AND STRONGER SHOWERS OR ISOLATED THUNDERSTORMS... BUT THE
CONFIDENCE LEVEL IS TOO LOW FOR MENTION ATTIM.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...05
SYNOPSIS...08
SHORT TERM...08
LONG TERM...DLF
AVIATION...05
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1000 PM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 959 PM CDT SUN APR 7 2013
UPDATED POPS/WX TO REFLECT THE LATEST RADAR TRENDS WITH THIS
EVENING`S THUNDERSTORM ACTIVITY. THUNDERSTORMS HAVE BEEN STEADILY
WEAKENING OVER THE LAST HOUR AND DIMINISHING IN COVERAGE ACROSS THE
FORECAST AREA. AS OF 03Z...THE LAST BAND OF THUNDERSTORMS WAS
TRACKING EAST ACROSS NORTHEASTERN KANSAS...HOWEVER A FEW ISOLATED
THUNDERSTORMS MAY STILL DEVELOP ACROSS EAST CENTRAL KANSAS THROUGH
LATE THIS EVENING. THESE LINGERING THUNDERSTORMS ARE ANTICIPATED TO
PROGRESS EAST OF THE CWA BY AROUND 06Z. AS A RESULT...HAVE TRENDED
WITH LOWERING POPS FROM WEST TO EAST ACROSS THE CWA THROUGH THE
REMAINDER OF THIS EVENING INTO THE EARLY OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
19Z WATER VAPOR IMAGERY SHOWS A QUASI-ZONAL FLOW ACROSS THE PLAINS
WITH A LOW AMPLITUDE SHORTWAVE MOVING ACROSS THE CO AND NM ROCKIES.
AT THE SURFACE A TROUGH OF LOW PRESSURE IN THE LEE OF THE ROCKIES
HAS STRENGTHENED AND CAUSED SOUTH AND SOUTHEAST WINDS TO INCREASE
BRINGING BETTER MOISTURE NORTH INTO SOUTHERN AND EASTERN KS.
THE UPPER WAVE IS EXPECTED TO MOVE ACROSS THE STATE THIS
EVENING...AND TRIGGER ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL KS. THIS ACTIVITY SHOULD MOVE ACROSS NORTHEAST KS THROUGH
THE EVENING. 18Z RUC SHOWS THE BETTER INSTABILITY CURRENTLY OVER
SOUTHERN KS WHERE THE DEWPOINTS ARE IN THE UPPER 50S. AS THE
SOUTHERLY WINDS CONTINUE TO BRING THE MOISTURE AND INSTABILITY INTO
EAST CENTRAL KS...THERE IS THE POTENTIAL THAT ANY CONVECTION IN
SOUTH CENTRAL KS COULD MOVE INTO THE AREA AND REMAIN ORGANIZED
ENOUGH FOR A SEVERE THREAT. PERHAPS THE GREATER THREAT FOR SEVERE
WEATHER MAY COME FROM ANY THUNDERSTORM DEVELOPMENT IN CENTRAL KS
THAT MOVES IN FROM THE WEST THIS EVENING. MODELS SHOW LOW LEVEL
SHEER INCREASING AS THE LOW LEVEL JET INCREASES. HOWEVER THE RAP
CONTINUES TO SHOW THE BEST INSTABILITY REMAINING ACROSS CENTRAL AND
SOUTHERN KS AND ALONG THE SOUTHWESTERN EDGE OF THE FORECAST AREA.
THERE COULD BE A SHORT WINDOW FOR SEVERE WEATHER IF DISCRETE STORMS
WERE ABLE TO FORM AND MOVE INTO THE AREA. GIVEN THE INCREASING 0-1KM
SHEER PARAMETERS...A TORNADO CAN NOT BE RULED OUT EITHER. EVENTUALLY
STORMS SHOULD BECOME MORE ELEVATED WITH CELL MERGERS DISRUPTING
UPDRAFT ORGANIZATION.
THINK THAT AS THE UPPER LEVEL WAVE PASSES EAST AROUND
MIDNIGHT...PRECIP CHANCES WILL QUICKLY DIMINISH OVERNIGHT. OVERNIGHT
LOWS SHOULD BE PRETTY MILD WITH CONTINUED SOUTH WINDS AND MOSTLY
CLOUDY SKIES PREVENTING MUCH IN THE WAY OF RADIATIONAL COOLING. SOME
OF THE OBJECTIVE GUIDANCE HAS LOW STRATUS MOVING IN WITH CONTINUED
MOISTURE ADVECTION FROM THE SOUTH. THEREFORE KEPT AT LEAST MOSTLY
CLOUDY SKIES IN THE FORECAST FOR TONIGHT.
FOR MONDAY FORECAST SOUNDINGS SHOW AN ELEVATED MIXED LAYER MOVING
OVER THE FORECAST AREA WITH LITTLE IN THE WAY OF LARGE SCALE FORCING
OR SURFACE BASED LIFT. BECAUSE OF THIS HAVE REMOVED POPS FOR MUCH OF
THE DAY THINKING THE BOUNDARY LAYER WILL REMAIN CAPPED. THE FORECAST
DOES SHOW CHANCES BEGINNING TO INCREASE LATE IN THE DAY AS DAY TIME
HEATING COULD CAUSE THE CAP TO WEAKEN ACROSS NORTH CENTRAL KS.
DEPENDING ON WHETHER THE LOW CLOUDS DEVELOP OR NOT...HIGHS SHOULD
MAKE IT INTO THE 70S. DID LOWER HIGHS A COUPLE DEGREES ACROSS EAST
CENTRAL KS WHERE CLOUDS ARE EXPECTED TO PERSIST LONGER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
BY THE EVENING HOURS ON MONDAY...A CONSIDERABLE EML MOVES OVER THE
MAJORITY OF THE CWA. HAVE BACKED OFF ON POPS AS A RESULT ALONG AND
SOUTH OF I70...AND MAY NEED TO BACK OFF EVEN MORE. TO THE
NORTH...THE CAP IS MUCH WEAKER...AND WOULD ANTICIPATE THAT BY
SUNRISE THERE WILL BE ENOUGH LIFT FROM THE LEADING WAVE AS WELL
AS CONVERGENCE IN THE LLJ AND THE SURFACE TROF FOR A LINE OF
THUNDERSTORMS ALONG THE KS NEBRASKA BORDER. COLD FRONT TO THE WEST
IS CONCURRENTLY SURGING TO THE SOUTHEAST AND MAY IMPINGE ON THE
FAR NW CORNER OF THE CWA BY AROUND 12Z TUESDAY...AND WILL CARRY
HIGHEST POPS TO THE NW.
CONDITIONS BY 12Z TUESDAY WILL BE IMPACTED BY PREVIOUS NIGHTS
WEATHER...BUT STILL APPEARS THAT LATE MORNING INTO THE EVENING
HOURS WILL BE THE GREATEST RISK FOR OUR FORECAST AREA FOR STRONG
TO SEVERE STORMS. THE DRYLINE AND FRONT COME TOGETHER OUT IN
WESTERN KANSAS IN THE MORNING AND BOTH MERGE AND MOVE INTO THE
WESTERN COUNTIES BY EARLY AFTERNOON. EC AND GFS SLIGHTLY SLOWER
AND COULD ALLOW FOR A BIT MORE BUILDUP OF INSTABILITY ACROSS THE
EAST BEFORE THE FRONT SURGES THROUGH LATE DAY. WITH WINDS THROUGH
THE COLUMN NEARLY RUNNING PARALLEL TO THE FRONT...DISCRETE CELLS
THAT INITIALLY FORM MAY EVOLVE QUICKLY INTO A LINE THAT ADVANCES
ACROSS THE CWA THROUGH THE EVENING HOURS. THIS WOULD MAKE SEVERE
WINDS THE PRIMARY CONCERN...ALTHOUGH WITH A QUICK INCREASE IN WIND
SPEEDS IN THE LOW LEVELS AND GOOD LOW LEVEL HELICITY CANT RULE OUT
ISOLATED TORNADOES...ESP IN EARLY ONSET OF THE CONVECTION AND IN
ANY STORMS THAT CAN FORM OUT IN THE WARM SECTOR.
TUESDAY NIGHT THROUGH FRIDAY BRING AN UNSEASONABLY COOL PERIOD AS
THE UPPER LOW CONTINUES TO DRAW COLDER AIR INTO THE PLAINS THROUGH
THE END OF THE WEEK. DAYTIME HIGHS WED WILL STRUGGLE TO REACH 40S
WHILE THURS AND FRI MAKE A SLOW CLIMB INTO THE MIDDLE 50S. BY THE
WEEKEND SOUTHERLY FLOW AT THE SURFACE AND WESTERLY FLOW ALOFT
BRING TEMPERATURES BACK TOWARD NORMAL WITH SOME CHANCES FOR RAIN
WITH SOME WEAK WAVES IN THE FLOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 639 PM CDT SUN APR 7 2013
FOR 00Z TAFS...MAIN FOCUS CONTINUES TO BE ON THE POTENTIAL FOR
SHOWERS AND THUNDERSTORMS THIS EVENING. SHORT-RANGE MODELS SHOW MORE
WIDESPREAD SCATTERED ACTIVITY DEVELOPING THROUGH THE EVENING
HOURS...IN WHICH CIG/VIS MAY DROP DOWN TO MVFR CONDITIONS AT TIMES.
MOST OF THIS ACTIVITY IS LOOKING TO PROGRESS EAST OF THE TAF SITES
DURING THE EARLY OVERNIGHT HOURS...HOWEVER SOUNDINGS SHOW PLENTY OF
LOW LEVEL MOISTURE REMAINING IN PLACE BEHIND THE
PRECIPITATION...RESULTING IN CIG/VIS POSSIBLY DROPPING DOWN TO IFR
CONDITIONS THROUGH MID MORNING BEFORE MIXING OUT AND LIFTING TO MVFR
CONDITIONS DURING THE LATE MORNING AND AFTERNOON HOURS. WINDS
THROUGH THE PERIOD WILL PREVAIL OUT OF THE SOUTH.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HENNECKE
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
640 PM CDT SUN APR 7 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
19Z WATER VAPOR IMAGERY SHOWS A QUASI-ZONAL FLOW ACROSS THE PLAINS
WITH A LOW AMPLITUDE SHORTWAVE MOVING ACROSS THE CO AND NM ROCKIES.
AT THE SURFACE A TROUGH OF LOW PRESSURE IN THE LEE OF THE ROCKIES
HAS STRENGTHENED AND CAUSED SOUTH AND SOUTHEAST WINDS TO INCREASE
BRINGING BETTER MOISTURE NORTH INTO SOUTHERN AND EASTERN KS.
THE UPPER WAVE IS EXPECTED TO MOVE ACROSS THE STATE THIS
EVENING...AND TRIGGER ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL KS. THIS ACTIVITY SHOULD MOVE ACROSS NORTHEAST KS THROUGH
THE EVENING. 18Z RUC SHOWS THE BETTER INSTABILITY CURRENTLY OVER
SOUTHERN KS WHERE THE DEWPOINTS ARE IN THE UPPER 50S. AS THE
SOUTHERLY WINDS CONTINUE TO BRING THE MOISTURE AND INSTABILITY INTO
EAST CENTRAL KS...THERE IS THE POTENTIAL THAT ANY CONVECTION IN
SOUTH CENTRAL KS COULD MOVE INTO THE AREA AND REMAIN ORGANIZED
ENOUGH FOR A SEVERE THREAT. PERHAPS THE GREATER THREAT FOR SEVERE
WEATHER MAY COME FROM ANY THUNDERSTORM DEVELOPMENT IN CENTRAL KS
THAT MOVES IN FROM THE WEST THIS EVENING. MODELS SHOW LOW LEVEL
SHEER INCREASING AS THE LOW LEVEL JET INCREASES. HOWEVER THE RAP
CONTINUES TO SHOW THE BEST INSTABILITY REMAINING ACROSS CENTRAL AND
SOUTHERN KS AND ALONG THE SOUTHWESTERN EDGE OF THE FORECAST AREA.
THERE COULD BE A SHORT WINDOW FOR SEVERE WEATHER IF DISCRETE STORMS
WERE ABLE TO FORM AND MOVE INTO THE AREA. GIVEN THE INCREASING 0-1KM
SHEER PARAMETERS...A TORNADO CAN NOT BE RULED OUT EITHER. EVENTUALLY
STORMS SHOULD BECOME MORE ELEVATED WITH CELL MERGERS DISRUPTING
UPDRAFT ORGANIZATION.
THINK THAT AS THE UPPER LEVEL WAVE PASSES EAST AROUND
MIDNIGHT...PRECIP CHANCES WILL QUICKLY DIMINISH OVERNIGHT. OVERNIGHT
LOWS SHOULD BE PRETTY MILD WITH CONTINUED SOUTH WINDS AND MOSTLY
CLOUDY SKIES PREVENTING MUCH IN THE WAY OF RADIATIONAL COOLING. SOME
OF THE OBJECTIVE GUIDANCE HAS LOW STRATUS MOVING IN WITH CONTINUED
MOISTURE ADVECTION FROM THE SOUTH. THEREFORE KEPT AT LEAST MOSTLY
CLOUDY SKIES IN THE FORECAST FOR TONIGHT.
FOR MONDAY FORECAST SOUNDINGS SHOW AN ELEVATED MIXED LAYER MOVING
OVER THE FORECAST AREA WITH LITTLE IN THE WAY OF LARGE SCALE FORCING
OR SURFACE BASED LIFT. BECAUSE OF THIS HAVE REMOVED POPS FOR MUCH OF
THE DAY THINKING THE BOUNDARY LAYER WILL REMAIN CAPPED. THE FORECAST
DOES SHOW CHANCES BEGINNING TO INCREASE LATE IN THE DAY AS DAY TIME
HEATING COULD CAUSE THE CAP TO WEAKEN ACROSS NORTH CENTRAL KS.
DEPENDING ON WHETHER THE LOW CLOUDS DEVELOP OR NOT...HIGHS SHOULD
MAKE IT INTO THE 70S. DID LOWER HIGHS A COUPLE DEGREES ACROSS EAST
CENTRAL KS WHERE CLOUDS ARE EXPECTED TO PERSIST LONGER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
BY THE EVENING HOURS ON MONDAY...A CONSIDERABLE EML MOVES OVER THE
MAJORITY OF THE CWA. HAVE BACKED OFF ON POPS AS A RESULT ALONG AND
SOUTH OF I70...AND MAY NEED TO BACK OFF EVEN MORE. TO THE
NORTH...THE CAP IS MUCH WEAKER...AND WOULD ANTICIPATE THAT BY
SUNRISE THERE WILL BE ENOUGH LIFT FROM THE LEADING WAVE AS WELL
AS CONVERGENCE IN THE LLJ AND THE SURFACE TROF FOR A LINE OF
THUNDERSTORMS ALONG THE KS NEBRASKA BORDER. COLD FRONT TO THE WEST
IS CONCURRENTLY SURGING TO THE SOUTHEAST AND MAY IMPINGE ON THE
FAR NW CORNER OF THE CWA BY AROUND 12Z TUESDAY...AND WILL CARRY
HIGHEST POPS TO THE NW.
CONDITIONS BY 12Z TUESDAY WILL BE IMPACTED BY PREVIOUS NIGHTS
WEATHER...BUT STILL APPEARS THAT LATE MORNING INTO THE EVENING
HOURS WILL BE THE GREATEST RISK FOR OUR FORECAST AREA FOR STRONG
TO SEVERE STORMS. THE DRYLINE AND FRONT COME TOGETHER OUT IN
WESTERN KANSAS IN THE MORNING AND BOTH MERGE AND MOVE INTO THE
WESTERN COUNTIES BY EARLY AFTERNOON. EC AND GFS SLIGHTLY SLOWER
AND COULD ALLOW FOR A BIT MORE BUILDUP OF INSTABILITY ACROSS THE
EAST BEFORE THE FRONT SURGES THROUGH LATE DAY. WITH WINDS THROUGH
THE COLUMN NEARLY RUNNING PARALLEL TO THE FRONT...DISCRETE CELLS
THAT INITIALLY FORM MAY EVOLVE QUICKLY INTO A LINE THAT ADVANCES
ACROSS THE CWA THROUGH THE EVENING HOURS. THIS WOULD MAKE SEVERE
WINDS THE PRIMARY CONCERN...ALTHOUGH WITH A QUICK INCREASE IN WIND
SPEEDS IN THE LOW LEVELS AND GOOD LOW LEVEL HELICITY CANT RULE OUT
ISOLATED TORNADOES...ESP IN EARLY ONSET OF THE CONVECTION AND IN
ANY STORMS THAT CAN FORM OUT IN THE WARM SECTOR.
TUESDAY NIGHT THROUGH FRIDAY BRING AN UNSEASONABLY COOL PERIOD AS
THE UPPER LOW CONTINUES TO DRAW COLDER AIR INTO THE PLAINS THROUGH
THE END OF THE WEEK. DAYTIME HIGHS WED WILL STRUGGLE TO REACH 40S
WHILE THURS AND FRI MAKE A SLOW CLIMB INTO THE MIDDLE 50S. BY THE
WEEKEND SOUTHERLY FLOW AT THE SURFACE AND WESTERLY FLOW ALOFT
BRING TEMPERATURES BACK TOWARD NORMAL WITH SOME CHANCES FOR RAIN
WITH SOME WEAK WAVES IN THE FLOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 639 PM CDT SUN APR 7 2013
FOR 00Z TAFS...MAIN FOCUS CONTINUES TO BE ON THE POTENTIAL FOR
SHOWERS AND THUNDERSTORMS THIS EVENING. SHORT-RANGE MODELS SHOW MORE
WIDESPREAD SCATTERED ACTIVITY DEVELOPING THROUGH THE EVENING
HOURS...IN WHICH CIG/VIS MAY DROP DOWN TO MVFR CONDITIONS AT TIMES.
MOST OF THIS ACTIVITY IS LOOKING TO PROGRESS EAST OF THE TAF SITES
DURING THE EARLY OVERNIGHT HOURS...HOWEVER SOUNDINGS SHOW PLENTY OF
LOW LEVEL MOISTURE REMAINING IN PLACE BEHIND THE
PRECIPITATION...RESULTING IN CIG/VIS POSSIBLY DROPPING DOWN TO IFR
CONDITIONS THROUGH MID MORNING BEFORE MIXING OUT AND LIFTING TO MVFR
CONDITIONS DURING THE LATE MORNING AND AFTERNOON HOURS. WINDS
THROUGH THE PERIOD WILL PREVAIL OUT OF THE SOUTH.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS PADUCAH KY
954 PM CDT SUN APR 7 2013
.MESOSCALE DISCUSSION...
ISSUED AT 953 PM CDT SUN APR 7 2013
A BRIEF UPDATE ON THE MESOSCALE CONVECTIVE SYSTEM/MESOSCALE
CONVECTIVE VORTEX MOVING THROUGH SOUTH CENTRAL MO. THIS FEATURE
HAS BEEN PRODUCING 1-1.75 INCH HAIL IN WFO SGF COUNTY WARNING AREA
EARLIER THIS EVENING. SPC ISSUED A MESOSCALE DISCUSSION NUMBER 396
ON THIS FEATURE AROUND 838 PM CDT.
ALTHOUGH THIS FEATURE CONTINUES TO BE MONITORED HERE AT WFO
PAH...THERE IS SOME INDICATIONS DURING THE LAST HOUR THROUGH LAPS
SURFACE THETA-E FIELDS...AS WELL AS THE 23Z HI-RES 3KM HRRR 1KM
REFLECTIVITY AND THE 00-1ZZ 13KM RAP MCS /MESOSCALE CONVECTIVE
SYSTEM/ PROBABILITY FIELDS THAT THIS FEATURE MAY CONTINUE AN EAST-
NORTHEAST TRAJECTORY TOWARD THE TWO PERRY COUNTIES /MO AND IL/
BEFORE DYING OUT AND GENERATING SOME DOWN STREAM CONVECTION ALONG
THE NORTHWARD RETREATING WARM FRONT. SCATTERED NON-SEVERE
POPS/WEATHER REMAIN IN PLACE FOR THOSE COUNTIES THROUGH MIDNIGHT.
SINCE THIS FEATURE HAS BEEN QUITE PERSISTENT BEYOND THE LIMITS OF
EARLIER GUIDANCE...WILL STILL NEED TO KEEP AN EYE ON IT FOR AT
LEAST SOME HAIL/WIND POTENTIAL.
&&
.UPDATE...
ISSUED AT 649 PM CDT SUN APR 7 2013
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 318 PM CDT SUN APR 7 2013
STILL NOTHING TOO DEFINITIVE WITH THE MODELS OVER THE NEXT FEW
PERIODS REGARDING SHOWER AND THUNDERSTORM CHANCES. AMOUNTS AND
TIMING OF BEST CHANCES IS QUITE VARIABLE WITH ALL THE MODELS...BUT
IT DOES AT LEAST LOOK LIKE THE BEST CHANCE OF ANY MEASURABLE
RAINFALL WILL BE ACROSS OUR NORTHERN COUNTIES. SHOWERS HAVE
FINALLY POPPED UP ALONG THE MISSISSIPPI RIVER JUST NORTH OF OUR
COUNTIES...SO WENT WITH SOME SLIGHT CHANCE POPS ACROSS OUR
NORTHERN COUNTIES BY MID EVENING...WITH POPS INCREASING TO LOW
CHANCE OVERNIGHT ESPECIALLY ALONG THE INTERSTATE 64 CORRIDOR.
ON MONDAY...BASED ON NAM AND SREF...KEPT KENTUCKY AND SOUTHERN PORTIONS
OF SOUTHEAST MISSOURI DRY...WITH SLIGHT TO LOW CHANCE POPS ACROSS
THE REST OF OUR COUNTIES. ECMWF AND GFS TRY TO GENERATE MORE
WIDESPREAD BUT SCATTERED PRECIP DURING THE DAY...BUT PREFER TO
LEAN TOWARD THE DRIER MODELS BASED ON THE POOR PERFORMANCE OF THE
WETTER MODELS TODAY. CONTINUED WITH THIS THINKING INTO MONDAY
NIGHT. CHANCES REMAIN LOW INTO TUESDAY...BUT THE ORIENTATION
CHANGES AS LOW PRESSURE SLIDES INTO THE CENTRAL PLAINS AND PRECIP
CHANCES IMPROVE A LITTLE FOR OUR WESTERN COUNTIES. WENT WITH
SLIGHT CHANCE POP FOR OUR WESTERN AND NORTHERN COUNTIES FOR TUESDAY.
TEMPERATURES WILL BE VERY WARM TONIGHT AND MONDAY NIGHT WITH SOME
CLOUDS AND PERSISTENT SOUTH WINDS. BREEZIER CONDITIONS ARE
EXPECTED MONDAY AND TUESDAY WITH GUSTS UP AROUND 25 MPH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 318 PM CDT SUN APR 7 2013
ACTIVE WEATHER TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS MID LEVEL
H5 TROF MOVES SLOWLY EAST FROM THE ROCKIES INTO THE PLAINS. A
SURFACE FRONT WILL BE JUST WEST OF THE AREA ACROSS CENTRAL SECTIONS
OF MISSOURI BY 12Z WED EXTENDING SOUTH INTO EAST TEXAS. IT WILL MOVE
SLOWLY EAST THROUGH THE DAY REACHING OUR FAR WESTERN COUNTIES BY THE
END OF THE DAY. CONVECTIVE ACTIVITY WILL BE ON THE INCREASE PEAKING
WEDNESDAY NIGHT WITH FROPA. LOCALLY HEAVY RAIN AND ISOLATED SEVERE
STORMS POSSIBLE ESPECIALLY WEDNESDAY AFTERNOON AND EVENING AND
ACROSS THE WEST 1/2 OF THE AREA. THE GFS IS STILL QUICKER TO END
PRECIP THURSDAY THAN THE ECMWF...THOUGH THE ECMWF IS TRENDING
SLIGHTLY FASTER...AND HAS A BIAS TO LAG PRECIP TOO LONG AT TIMES.
UNTIL THE PARENT TROF MOVES ACROSS THE AREA THURSDAY...HARD TO RULE
OUT LINGERING SMALL CHANCE POPS. FORECASTING DRY WEATHER FRIDAY ON
INTO THE WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION.
&&
.AVIATION...
ISSUED AT 649 PM CDT SUN APR 7 2013
LATEST SATELLITE IMAGERY SUGGESTS THAT WE MAY SEE MOSTLY CLEAR
SKIES FOR MUCH OF THE EVENING...BEFORE CLOUDS IN THE 3-5KFT LAYER
SPREAD BACK NORTHWARD ACROSS THE REGION OVERNIGHT. GUIDANCE
INDICATES THAT WINDS MAY DROP OFF SIGNIFICANTLY FOR A FEW HOURS
THIS EVENING BEFORE STRENGTHENING BACK AROUND 8 OR 9KTS OVERNIGHT.
HAVE A MIXED SIGNAL IN LATEST GUIDANCE FOR TIMING ANY MVFR
CEILINGS LATE TONIGHT OR MONDAY. CURRENT FEELING IS THAT MVFR
CEILINGS WILL BE SLOW TO SET IN AT KCGI AND KPAH...BUT THEY MAY
LINGER THROUGH THE AFTERNOON ONCE THEY ARRIVE. LOOKS LIKE THEY
WILL ARRIVE MID-MORNING AT KOWB AND KEVV...AND THEN LIFT/SCATTER
BY EARLY AFTERNOON. SOUTH TO SOUTHWEST WINDS WILL GUST UP TO NEAR
25KTS AT TIMES FROM MID-MORNING THROUGH THE AFTERNOON. OF COURSE
WOULD EXPECT THE GREATEST MIXING/GUSTS TO OCCUR WHEN/WHERE LOW CLOUDS
SCATTER OUT.
INSERTED A VCSH AT KCGI AND KEVV FOR THE AFTERNOON AS MOST GUIDANCE
INDICATES A WEAK MID LEVEL DISTURBANCE PUSHING EASTWARD THROUGH
THE AREA. WOULD BE SURPRISED TO SEE ANYTHING SIGNIFICANT TO
AVIATION AT THE TERMINALS...BUT WANTED TO HINT THAT THERE COULD BE
SOME SHOWERS AROUND.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
MESOSCALE...SMITH
UPDATE...DRS
SHORT TERM...RST
LONG TERM...CN
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS GRAY ME
1011 PM EDT SUN APR 7 2013
.SYNOPSIS...
LOW PRESSURE CROSSING SOUTHERN CANADA WILL DRAG A COLD FRONT
THROUGH THE REGION OVERNIGHT. A WEAK AREA OF HIGH PRESSURE WILL
BUILD OVER THE REGION ON MONDAY. ANOTHER AREA OF LOW PRESSURE
WILL HEAD EAST FROM THE GREAT LAKES MONDAY NIGHT AND WILL MOVE
THROUGH SOUTHERN NEW ENGLAND AND OUT TO SEA ON TUESDAY. LOW
PRESSURE WILL ONCE AGAIN APPROACH FROM THE WEST TUESDAY NIGHT
LIFTING A WARM FRONT INTO CENTRAL NEW ENGLAND ON WEDNESDAY WHERE
IT WILL STALL. LOW PRESSURE MOVING NORTHEAST THROUGH THE ST
LAWRENCE VALLEY WILL LIFT THE WARM FRONT INTO NORTHERN NEW ENGLAND
ON THURSDAY. A TRAILING COLD FRONT WILL CROSS THE AREA THURSDAY
NIGHT AND WILL SLOWLY PUSH OFFSHORE ON FRIDAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST SATURDAY THROUGH SUNDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
UPDATE...
HAVE UPDATED GRIDS TO ACCOUNT FOR CURRENT CONDITIONS. WINDS
CONTINUE TO BE GUSTING BETWEEN 20 AND 25 MPH IN PLACES ACROSS THE
FORECAST AREA...WITH HIGHEST GUSTS ALONG THE EXPOSED
COASTLINE...AND ALSO OVER IN NH WHERE TEMPERATURES CLIMBED WELL
INTO THE 50S. HWVR...TREND WILL BE FOR THESE WINDS TO SUBSIDE OVER
THE NEXT FEW HOURS.
HAVE REMOVED FZRA FROM TNGTS FCST AS GROUND TEMPS SEEM A LITTLE
TOO WARM WITH READINGS CURRENTLY IN THE 50S IN THE MTNS. HAVE ALSO
USED THE "SHOWERIZE" TOOL FOR TNGTS PCPN.
LATEST RUC SOLUTION CONTINUES TO INDICATE A FEW MORE SHOWERS WILL
MOVE ACROSS NRN PTNS OF THE FA...NEAR THE WRN MTNS OF MAINE
THROUGH ABOUT 06Z. SOME OF THIS SCT SHOWERS AND LCLZD ICE PELLOTS WILL
SLOWLY DRY UP AS IT MOVES ACROSS THE REGION.
HAVE ADJUSTED DEW POINTS BASED ON CURRENT CONDITIONS. ALSO...USED
CLOUD COVER FROM STLT FOR THE INTIAL CONDS AS CLOUD DECKS ARE
RAPIDLY CHANGING.
PREV DISC...
LOW PRESSURE CROSSING SOUTHERN CANADA WILL DRAG A COLD FRONT
THROUGH THE REGION OVERNIGHT. SHOWERS AND A FEW THUNDERSTORMS
CURRENTLY PUSHING THROUGH EASTERN NEW YORK AHEAD OF THE FRONT AND
THIS LINE WILL BRING THE BEST CHANCE OF PRECIP TO THE REGION
DURING THE EVENING HOURS. MAY SEE SOME SLEET OR SNOW GRAINS MIXING
IN IN THE NORTH BUT NOT LOOKING FOR ANY ACCUMULATIONS. SHOULD SEE
PARTIAL CLEARING DOWNWIND OF THE MOUNTAINS DURING THE EARLY
MORNING HOURS WHILE CLOUDS PERSIST IN THE NORTH. WILL SEE A
RELATIVELY MILD NIGHT WITH LOWS IN THE LOWER TO MID 30S NORTH AND
UPPER 30S TO LOWER 40S IN THE SOUTH.
&&
.SHORT TERM /MONDAY NIGHT/...
MOUNTAIN CLOUDS WILL GRADUALLY DIMINISH MONDAY MORNING AND SHOULD
SEE MOSTLY SUNNY SKIES ACROSS THE REGION BY AFTERNOON AS A WEAK
RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION. WILL SEE TEMPS
REBOUND TO ABOVE NORMAL...ALTHOUGH EXPECT AN AFTERNOON SEA BREEZE
TO CAP HIGHS IN THE MID TO UPPER 50S IN COASTAL AREAS. WARMER
SOUTHERN INTERIOR SECTIONS WILL ENJOY HIGHS IN THE LOWER TO MID 60S.
RAPID FIRE PROCESSION SHORTWAVES WILL CONTINUE MONDAY NIGHT AS LOW
PRESSURE QUICKLY HEADS EAST FROM THE GREAT LAKES. CLOUDS WILL
OVERSPREAD THE REGION FROM WEST TO EAST DURING THE EVENING HOURS
WITH RAIN MOVING INTO MUCH OF THE REGION AROUND MIDNIGHT. MAY SEE
ENOUGH COOLING FOR RAIN TO MIX WITH SLEET OR SNOW IN THE NORTH
WHERE AN INCH OR TWO OF WET SNOW MAY ACCUMULATE OVER THE HIGHER
TERRAIN. WILL ONCE AGAIN SEE MILD OVERNIGHT LOWS WITH MID TO UPPER
30S NORTH AND UPPER 30S TO LOWER 40S SOUTH.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
SFC LOW TRACKS ACROSS THE FCST AREA TUESDAY WITH RA/SHRA THRU THE
MORNING IN NH AND MIDDAY OVER ME...THEN AS THE LOW MOVES QUICKLY TO
THE E CLEARING FOLLOWS FROM W TO E. A TRAILING FNT DEVELOPS W OF THE
LOW ACROSS THE FCST AREA AND FURTHER TO THE W TUESDAY NGT. THIS FNT
SEPARATES MUCH WARMER AIR TO THE S FROM MUCH COLDER AIR TO THE N.
THE FNT SAGS SLOWLY TO THE S ON WEDNESDAY WITH VERY WEAK LOW PRES
SLIDING TO THE E ALONG THE BOUNDARY. THE FNT WAVERS WEDNESDAY NGT
THRU THURSDAY NGT AS OTHER WEAK LOWS TRACK EASTWARD ALONG IT. THE
EXACT LOCATION OF THE FNT VARIES AMONGST THE MODELS WITH THE ECMWF
THE COLDEST WITH THE BOUNDARY TO OUR S, GFS THE WARMEST WITH THE FNT
JUST TO OUR N AND THE CMC MODEL IN BETWEEN THOUGH CLOSER TO THE GFS.
EITHER WAY THE SYSTEM WILL GIVE US A PERIOD OF WET WX...MOSTLY
RA...THOUGH SOME MIX OR MAYBE SN OVER FAR NORTHERN AND MOUNTAIN ZONES
PSBL. THE GFS WARMS US UP CONSIDERABLY WITH H8 TEMPS OF PLUS 10 TO
NEARLY PLUS 15. THIS APPEARS OVERDONE THOUGH THE ECMWF WHICH IS MUCH
COLDER MAY ALSO BE OVERDONE... SO A COMPROMISE IS IN ORDER.
FINALLY THE LAST LOW MOVES E ON FRIDAY WITH A TRAILING CD FNT ALSO
PUSHING TO THE E. TIMING OF THIS SYSTEM STILL TO EARLY TO DETERMINE
WHETHER OR NOT WE SEE PRCP FOR MOST OF THE DAY OR IF IT COMES TO
AN END EARLIER ON. ALSO...THE ECMWF IS TRACKING THE LOW TO OUR S
RATHER THAN OVER US LIKE THE GFS THUS THE ECMWF MODEL PROVIDES A
BETTER CHC FOR MIXED/SN EVENT ON FRIDAY.
BEHIND THIS SYSTEM STRONG GUSTY NW WINDS USHER IN COLDER AND DRIER
AIR FRIDAY NGT AND SATURDAY. HIGH PRES BUILDS IN ON SUNDAY WITH
WEAKER WINDS AND WARMING TEMPS AS THE AIR MASS MODERATES.
GENERALLY USED BLEND OF ECMWF, GFS40, NAM, HPC GUIDANCE, GMOS AND
MEX MOS AND WNA4 FOR SEAS FOR THE LONG TERM FCST.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
SHORT TERM...AREAS OF MVFR/IFR CEILINGS TONIGHT...BECOMING VFR ON
MONDAY. MORE MVFR/IFR CEILINGS DEVELOPING AFTER MIDNIGHT MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...AN LENGTHY PERIOD OF UNSETTLED
WET WEATHER THRU THE LONG TERM PERIOD AS A FRONTAL BOUNDARY STAYS
NEARBY WHILE LOW PRES SYSTEMS TRACK E ALONG IT. THUS FREQUENT
IFR/LIFR CONDITIONS PSBL TUESDAY THRU FRIDAY.
&&
.MARINE...
SHORT TERM...CONTINUING SCA`S THROUGH TONIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...
UPDATE...
HAVE EXTENDED THE SCAS INTO MONDAY FOR THE OUTER WATERS. THIS IS
MAINLY DUE TO SEAS.
PREV DISC...
CONDITIONS MAINLY BELOW SCA
LEVELS TUESDAY THRU WEDNESDAY NGT AS FNT REMAINS NEARBY AND PRES
GRADIENT FAIRLY WEAK AS WEAK LOW PRES MOVES ALONG THE FNT.
THURSDAY THRU FRIDAY...DEPENDING ON THE MODEL SOLUTION... THERE IS
THE POTENTIAL FOR A MORE SIGNIFICANT LOW TO FORM WHICH WOULD
INCREASE WINDS AND BUILD SEAS POSSIBLY TO SCA LEVELS...OR MAYBE
INTO MINIMAL GALE FORCE OVER THE OUTER WATERS.
&&
.FIRE WEATHER...
RAIN SHOWERS WILL HELP TO DAMPEN FIRE DANGER
OVERNIGHT. WARMER TEMPS AND HIGHER DEW POINTS WILL KEEP THE REGION
ABOVE RED FLAG CRITERIA MONDAY WITH ANOTHER ROUND OF SHOWERS
COMING THROUGH MONDAY NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ151-153.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT MONDAY FOR ANZ150-152-154.
&&
$$H
AREA FORECAST DISCUSSION
NWS GRAY ME
721 PM EDT SUN APR 7 2013
.SYNOPSIS...
LOW PRESSURE CROSSING SOUTHERN CANADA WILL DRAG A COLD FRONT
THROUGH THE REGION OVERNIGHT. A WEAK AREA OF HIGH PRESSURE WILL
BUILD OVER THE REGION ON MONDAY. ANOTHER AREA OF LOW PRESSURE
WILL HEAD EAST FROM THE GREAT LAKES MONDAY NIGHT AND WILL MOVE
THROUGH SOUTHERN NEW ENGLAND AND OUT TO SEA ON TUESDAY. LOW
PRESSURE WILL ONCE AGAIN APPROACH FROM THE WEST TUESDAY NIGHT
LIFTING A WARM FRONT INTO CENTRAL NEW ENGLAND ON WEDNESDAY WHERE
IT WILL STALL. LOW PRESSURE MOVING NORTHEAST THROUGH THE ST
LAWRENCE VALLEY WILL LIFT THE WARM FRONT INTO NORTHERN NEW ENGLAND
ON THURSDAY. A TRAILING COLD FRONT WILL CROSS THE AREA THURSDAY
NIGHT AND WILL SLOWLY PUSH OFFSHORE ON FRIDAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST SATURDAY THROUGH SUNDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
UPDATE...
HAVE UPDATED GRIDS TO ACCOUNT FOR CURRENT CONDITIONS. WINDS
CONTINUE TO GUST BETWEEN 20 AND 30 MPH ACROSS THE FORECAST
AREA...WITH HIGHEST GUSTS ALONG THE EXPOSED COASTLINE...AND ALSO
OVER IN NH WHERE TEMPERATURES CLIMBED WELL INTO THE 50S.
HAVE REMOVED FZRA FROM TNGTS FCST AS GROUND TEMPS SEEM A LITTLE
TOO WARM WITH READINGS CURRENTLY IN THE 50S IN THE MTNS. HAVE ALSO
USED THE "SHOWERIZE" TOOL FOR TNGTS PCPN.
LATEST RUC SOLUTION PICKS UP ON CONVECTIVE LINE ALONG THE VT/NH
BORDER (AS OF 2032Z) VERY WELL. HOWEVER...THIS LINE OF PCPN SHOULD
WEAKEN SIGNIFICANTLY AS IT ENTERS THE REGION OF MUCH LOWER SURFACE
DEW POINTS.
HAVE ADJUSTED DEW POINTS BASED ON CURRENT CONDITIONS. ALSO...USED
CLOUD COVER FROM STLT FOR THE INTIAL CONDS AS CLOUD DECKS ARE
RAPIDLY CHANGING.
PREV DISC...
LOW PRESSURE CROSSING SOUTHERN CANADA WILL DRAG A COLD FRONT
THROUGH THE REGION OVERNIGHT. SHOWERS AND A FEW THUNDERSTORMS
CURRENTLY PUSHING THROUGH EASTERN NEW YORK AHEAD OF THE FRONT AND
THIS LINE WILL BRING THE BEST CHANCE OF PRECIP TO THE REGION
DURING THE EVENING HOURS. MAY SEE SOME SLEET OR SNOW GRAINS MIXING
IN IN THE NORTH BUT NOT LOOKING FOR ANY ACCUMULATIONS. SHOULD SEE
PARTIAL CLEARING DOWNWIND OF THE MOUNTAINS DURING THE EARLY
MORNING HOURS WHILE CLOUDS PERSIST IN THE NORTH. WILL SEE A
RELATIVELY MILD NIGHT WITH LOWS IN THE LOWER TO MID 30S NORTH AND
UPPER 30S TO LOWER 40S IN THE SOUTH.
&&
.SHORT TERM /MONDAY NIGHT/...
MOUNTAIN CLOUDS WILL GRADUALLY DIMINISH MONDAY MORNING AND SHOULD
SEE MOSTLY SUNNY SKIES ACROSS THE REGION BY AFTERNOON AS A WEAK
RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION. WILL SEE TEMPS
REBOUND TO ABOVE NORMAL...ALTHOUGH EXPECT AN AFTERNOON SEA BREEZE
TO CAP HIGHS IN THE MID TO UPPER 50S IN COASTAL AREAS. WARMER
SOUTHERN INTERIOR SECTIONS WILL ENJOY HIGHS IN THE LOWER TO MID 60S.
RAPID FIRE PROCESSION SHORTWAVES WILL CONTINUE MONDAY NIGHT AS LOW
PRESSURE QUICKLY HEADS EAST FROM THE GREAT LAKES. CLOUDS WILL
OVERSPREAD THE REGION FROM WEST TO EAST DURING THE EVENING HOURS
WITH RAIN MOVING INTO MUCH OF THE REGION AROUND MIDNIGHT. MAY SEE
ENOUGH COOLING FOR RAIN TO MIX WITH SLEET OR SNOW IN THE NORTH
WHERE AN INCH OR TWO OF WET SNOW MAY ACCUMULATE OVER THE HIGHER
TERRAIN. WILL ONCE AGAIN SEE MILD OVERNIGHT LOWS WITH MID TO UPPER
30S NORTH AND UPPER 30S TO LOWER 40S SOUTH.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
SFC LOW TRACKS ACROSS THE FCST AREA TUESDAY WITH RA/SHRA THRU THE
MORNING IN NH AND MIDDAY OVER ME...THEN AS THE LOW MOVES QUICKLY TO
THE E CLEARING FOLLOWS FROM W TO E. A TRAILING FNT DEVELOPS W OF THE
LOW ACROSS THE FCST AREA AND FURTHER TO THE W TUESDAY NGT. THIS FNT
SEPARATES MUCH WARMER AIR TO THE S FROM MUCH COLDER AIR TO THE N.
THE FNT SAGS SLOWLY TO THE S ON WEDNESDAY WITH VERY WEAK LOW PRES
SLIDING TO THE E ALONG THE BOUNDARY. THE FNT WAVERS WEDNESDAY NGT
THRU THURSDAY NGT AS OTHER WEAK LOWS TRACK EASTWARD ALONG IT. THE
EXACT LOCATION OF THE FNT VARIES AMONGST THE MODELS WITH THE ECMWF
THE COLDEST WITH THE BOUNDARY TO OUR S, GFS THE WARMEST WITH THE FNT
JUST TO OUR N AND THE CMC MODEL IN BETWEEN THOUGH CLOSER TO THE GFS.
EITHER WAY THE SYSTEM WILL GIVE US A PERIOD OF WET WX...MOSTLY
RA...THOUGH SOME MIX OR MAYBE SN OVER FAR NORTHERN AND MOUNTAIN ZONES
PSBL. THE GFS WARMS US UP CONSIDERABLY WITH H8 TEMPS OF PLUS 10 TO
NEARLY PLUS 15. THIS APPEARS OVERDONE THOUGH THE ECMWF WHICH IS MUCH
COLDER MAY ALSO BE OVERDONE... SO A COMPROMISE IS IN ORDER.
FINALLY THE LAST LOW MOVES E ON FRIDAY WITH A TRAILING CD FNT ALSO
PUSHING TO THE E. TIMING OF THIS SYSTEM STILL TO EARLY TO DETERMINE
WHETHER OR NOT WE SEE PRCP FOR MOST OF THE DAY OR IF IT COMES TO
AN END EARLIER ON. ALSO...THE ECMWF IS TRACKING THE LOW TO OUR S
RATHER THAN OVER US LIKE THE GFS THUS THE ECMWF MODEL PROVIDES A
BETTER CHC FOR MIXED/SN EVENT ON FRIDAY.
BEHIND THIS SYSTEM STRONG GUSTY NW WINDS USHER IN COLDER AND DRIER
AIR FRIDAY NGT AND SATURDAY. HIGH PRES BUILDS IN ON SUNDAY WITH
WEAKER WINDS AND WARMING TEMPS AS THE AIR MASS MODERATES.
GENERALLY USED BLEND OF ECMWF, GFS40, NAM, HPC GUIDANCE, GMOS AND
MEX MOS AND WNA4 FOR SEAS FOR THE LONG TERM FCST.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
SHORT TERM...AREAS OF MVFR/IFR CEILINGS TONIGHT...BECOMING VFR ON
MONDAY. MORE MVFR/IFR CEILINGS DEVELOPING AFTER MIDNIGHT MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...AN LENGTHY PERIOD OF UNSETTLED
WET WEATHER THRU THE LONG TERM PERIOD AS A FRONTAL BOUNDARY STAYS
NEARBY WHILE LOW PRES SYSTEMS TRACK E ALONG IT. THUS FREQUENT
IFR/LIFR CONDITIONS PSBL TUESDAY THRU FRIDAY.
&&
.MARINE...
SHORT TERM...CONTINUING SCA`S THROUGH TONIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...
UPDATE...
HAVE EXTENDED THE SCAS INTO MONDAY FOR THE OUTER WATERS. THIS IS
MAINLY DUE TO SEAS.
PREV DISC...
CONDITIONS MAINLY BELOW SCA
LEVELS TUESDAY THRU WEDNESDAY NGT AS FNT REMAINS NEARBY AND PRES
GRADIENT FAIRLY WEAK AS WEAK LOW PRES MOVES ALONG THE FNT.
THURSDAY THRU FRIDAY...DEPENDING ON THE MODEL SOLUTION... THERE IS
THE POTENTIAL FOR A MORE SIGNIFICANT LOW TO FORM WHICH WOULD
INCREASE WINDS AND BUILD SEAS POSSIBLY TO SCA LEVELS...OR MAYBE
INTO MINIMAL GALE FORCE OVER THE OUTER WATERS.
&&
.FIRE WEATHER...
RAIN SHOWERS WILL HELP TO DAMPEN FIRE DANGER
OVERNIGHT. WARMER TEMPS AND HIGHER DEW POINTS WILL KEEP THE REGION
ABOVE RED FLAG CRITERIA MONDAY WITH ANOTHER ROUND OF SHOWERS
COMING THROUGH MONDAY NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ151-153.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT MONDAY FOR ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
631 PM EDT SAT APR 6 2013
.SYNOPSIS...
HIGH PRESSURE AND DRY WEATHER WILL CONTINUE OVERNIGHT. A FRONTAL
SYSTEM WILL APPROACH ON SUNDAY BRINGING SCATTERED SHOWERS. THE
FRONT WILL LINGER NEARBY INTO NEXT WEEK WITH A CONTINUED CHANCE OF SHOWERS.
&&
.NEAR TERM /THROUGH SUNDAY/...
630 PM UPDATE...TEMPERATURES DROPPING EARLY THIS EVENING WITH
CONTINUED LOW DEW POINTS. HRRR SUGGESTING NO LOW CLOUDS OVERNIGHT
WITH LACK OF LOW LEVEL MOISTURE AND ONLY SCATTERED TO BROKEN MID
DECK AND CIRRUS. WILL ADJUST TEMPERATURE TREND AND LOWER MINIMUMS
SLIGHTLY GIVEN DEW POINTS AND EXPECTED CLOUDS.
PREVIOUS DISCUSSION FOLLOWS...
DEWPOINTS HAVE LARGELY RUN IN THE SINGLE DIGITS THROUGH MOST OF
THE AFTERNOON TODAY...WITH A FEW LOCATIONS JUST SOUTH OF OUR AREA
IN WEST VIRGINIA RUNNING WELL BELOW ZERO. THE RESULT HAS BEEN AN
EXTREMELY DRY DAY ACROSS THE FORECAST AREA WITH ONLY CIRRUS
GENERALLY FILTERING THE SUN. AS THE NIGHT ENSUES...MORE
SIGNIFICANT LARGE SCALE LIFT AND MOISTURE SLOWLY ENCROACHES FROM
THE WEST...HOWEVER GIVEN THAT IT HAS FAILED TO EVEN REACH THE
MIDDLE AND UPPER MISSISSIPPI VALLEY THIS AFTERNOON...AND THE FACT
THAT THE BEST UPPER LEVEL RH FIELDS FAVOR CIRRUS AND MID-CLOUD
DEVELOPMENT LARGELY NORTH OF THE AREA...THE NIGH SHOULD BE DRY
ALMOST EVERYWHERE IN THE FORECAST AREA...WITH ONLY HIGH CLOUDS
FILTERING THE MOON OUT FROM TIME TO TIME. DUE TO THE RIDICULOUSLY
DRY IN SITU BOUNDARY LAYER AND LACK OF SIGNIFICANT LAYER RH COMING
INTO THE FORECAST AREA BEFORE MORNING...ALL POPS WERE REMOVED FOR
THE NIGHT.
WITH OUR EXTREMELY DRY BOUNDARY LAYER THIS AFTERNOON AND LESS
SIGNIFICANT CLOUD EXPECTATIONS...LOW TEMPERATURES WERE CUT A BIT
OVERNIGHT...HOWEVER IT WILL NOT BE ANYWHERE NEAR AS COLD AS RECENT
NIGHTS. ADDITIONALLY...SURFACE FLOW SHOULD SLOWLY TURN
SOUTHERLY...WHICH WILL ALSO WORK TO LIMIT THE DIURNAL FALL
POTENTIAL. FRIES
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
NAM AND GFS SOLUTIONS HAVE COME INTO DECENT AGREEMENT WITH A
FRONTAL PASSAGE THROUGH THE AREA ON SUNDAY. MOISTURE ALONG AND
AHEAD OF THE FRONT IS RATHER LIMITED AS IT MOVES INTO OUR BONE DRY
ENVIRONMENT...SO QPF VALUES WERE CUT BACK QUITE A BIT.
HOWEVER...DECENT FRONTOGENETICAL FORCING AS WELL AS SOME SHALLOW
INSTABILITY SHOULD BE ENOUGH TO GENERATE A LINE OF LIGHT SHOWERS
ALONG THE FRONT AS IT MOVES THROUGH SUNDAY.
THE MODEL CONSENSUS FAVORS A STALLING OF THE FRONT ACROSS NORTHERN
WEST VIRGINIA SUNDAY NIGHT BEFORE IT TURNS NORTHWARD AS A WARM
FRONT ON MONDAY. THIS BRINGS PROGRESSIVELY WARMER AIR INTO THE
AREA EARLY NEXT WEEK. POPS FOR SHOWERS WERE CONTINUE THROUGH
MONDAY NIGHT BEFORE BEING INCREASED AGAIN ON TUESDAY. WHILE
AGREEMENT ON THE PLACEMENT OF THE FRONT BY TUESDAY BECOMES LESS
PRONOUNCED...THE ECMWF/GFS/NAM ALL LIKE THE IDEA OF TRACKING A
WAVE DOWN THE FRONT BY THE AFTERNOON HOURS. THIS WOULD ADD
ADDITIONAL LIFT AND SHEAR ALONG THE FRONTAL ZONE. IN
ADDITION...SYNOPTIC LIFT MAY BE ENOUGH TO OVERCOME A MODERATELY
STRONG CAP ALONG THE FRONTAL BOUNDARY. IF THIS OCCURS...A FEW
HUNDRED J/KG OF CAPE ARE PRESENT BY TUESDAY THAT DOES MANAGE TO
REACH UP TOWARD THE -30C ISOTHERM. THIS WOULD YIELD A CHANCE OF
THUNDERSTORMS BY TUESDAY AFTERNOON. THUNDERSTORMS WERE THUS ADDED
TO THE FORECAST FOR TUESDAY AFTERNOON...HOWEVER REMAIN OUT OF THE
FORECAST BEFORE THAT TIME DUE TO SHALLOW INSTABILITY AND CAPPING.
FRIES
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OVERALL...CONFIDENCE IN EXTENDED FORECAST IS LOWER THAN
NORMAL...SIMILAR TO YESTERDAY. FRONT WILL STILL BE HUNG UP TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...PROBABLY TO THE NORTH OF THE REGION.
ALTHOUGH COLD FRONT WILL LIKELY BEGIN TO CROSS THE REGION ON
THURSDAY...GFS/ECMWF CANNOT DECIDE WHETHER THE COLD FRONT WILL TAKE
24 OR 48 HOURS TO PUSH ALL THE WAY THROUGH. HAVE BUMPED UP POPS TO
LIKELY THURSDAY NIGHT...BUT OTHERWISE MADE LITTLE CHANGES TO POPS OR
TEMPERATURES. TEMPERATURES SHOULD BE ABOVE NORMAL
WED/THURS...DROPPING TO BELOW NORMAL FRI/SAT.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
MID LEVEL CLOUDS CONTINUE TO DISSIPATE AS THEY APPROACH EASTERN
OHIO DUE TO THE VERY DRY AIR. EXPECT ONLY SCATTERED HIGH CLOUDS
FOR THE AFTERNOON AND EVENING. HAVE ADDED LOW LEVEL WIND SHEAR IN
THE TAFS OVERNIGHT WITH LOW LEVEL JET DEVELOPING. HAVE GONE WITH
SHOWERS IN THE TAFS IN SOME LOCATION LATE SUNDAY MORNING...WITH
FRONT CROSSING THE REGION BETWEEN 15Z-21Z. WHILE THERE IS SOME
MODEL GUIDANCE THAT CIGS COULD DROP TO MVFR IN RAIN...DID NOT HAVE
ENOUGH CONFIDENCE TO INCLUDE IN TAFS AT THIS TIME.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
THE BOUNDARY SHOULD SHIFT SOUTH OF THE REGION SUNDAY NIGHT...THEN
BE PULLED NORTHWARD ONCE AGAIN ON MONDAY AS LOW PRES DIGS ACRS THE
GREAT LAKES. FRONT POSITIONING IS QUESTIONABLE THROUGH MUCH OF THE
WEEK...SO OCCASIONAL RESTRICTIONS SHOULD BE ANTICIPATED.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
702 PM EDT SAT APR 6 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 507 PM EDT SAT APR 6 2013
FIGURING OUT THIS MESSY SPRING SYSTEM CONTINUES TO BE A DIFFICULT
PROPOSITION.
999MB SFC LOW CONTINUES TO TRACK EAST ACROSS MINNESOTA...JUST TO
SOUTH OF TWIN CITIES AS OF 19Z. SFC WARM FRONT WELL TO SOUTH ACROSS
SOUTHERN WI. TEMP OF 60F AT MSN. READINGS NEAR 40F ARE CLOSING IN ON
WI BORDER. REMAINS IN THE LOW-MID 30S ELSEWHERE...COLDEST OVR THE
KEWEENAW PENINSULA AND OUT IN THE FAR EASTERN CWA AROUND KERY.
LARGER SCALE QUITE THE MESS AS THERE ARE MULTIPLE SHORTWAVES AND
MORE OF A SPLIT TROUGH LOOK AT H7-H5. NORTHERN STREAM WAVE IS
STRONGER THAN EXPECTED AND THIS HAS ALLOWED FOR STRONGER H925-H85
TROUGH TO DRAW WARM AIR AT 975-850MB INTO UPR MICHIGAN. CURRENT
RADAR SHOWS INITIAL WARM AIR ADVECTION SNOW IS 1-2 HRS FROM ENDING
AT KERY AND THERE HAS BEEN A DECENT LULL THAT OCCURED THIS AFTN OVR
MUCH OF THE CWA...EXCEPT ACROSS THE KEWEENAW WHERE SNOW HAS BEEN
STEADY MOST OF THE DAY.
UPSTREAM THOSE MULTIPLE SHORTWAVE TROUGHS ARE RESULTING IN MANY
AREAS OF PRECIPITATION. STRONGEST AREA OF PRECIP IS TIED TO
NORTHERN WAVE...WITH WIDESPREAD PRECIPITATION OVER NORTHEAST
MINNESOTA. CLUSTERS OF PRECIP ARE ALSO FILLING IN AHEAD OF SOUTHERN
STREAM WAVE AND SFC LOW OVER ECNTRL MN AND ALONG SFC WARM FRONT OVER
SOUTHERN WI. GRADUALLY THESE TWO SHORTWAVE TROUGHS ARE SHOWN TO PHASE
OVER WI/LK MICHIGAN TONIGHT...ALLOWING PRECIPITATION TO EXPAND OVR
MUCH OF CWA. FOLLOWING 975-950MB TEMPS FROM RUC/NAM/GFS POINTS TO
RAIN BEING DOMINANT PTYPE EARLY THIS EVENING OVER ALL BUT KEWEENAW
PENINSULA. HEAVIER PRECIPITATION MOVING OVER KDLH IN LAST HOUR HAS
PRODUCED RA/FZRA/PL/SN...EVEN AS RUC WARM LAYER WAS WELL ABOVE 0C.
THIS IS CERTAINLY THE DYNAMIC COOLING THAT MODELS WERE HINTING AT
ON FRIDAY. HINTS FROM NAM/GFS AND HRRR...WHICH IS HANDLING CURRENT
PRECIP TRENDS QUITE WELL...THAT SIMILAR SITUATION MAY OCCUR MID-LATE
EVENING OVER WESTERN THIRD OF CWA. TRIED TO SHOW THIS IN PYTPE GRIDS
AND ALSO INCREASED SNOWFALL AMOUNTS INTO 2-4 INCH RANGE FROM IRONWOOD
TO HOUGHTON AND INTO THE HURON MOUNTANS. ELSEWHERE THOUGH LATE EVENING
DO NOT EXPECT MUCH SNOW AT ALL AS WARM AIR ALOFT DOMINATES.
LATE EVENING INTO THE EARLY OVERNIGHT CHANGEOVER FROM RAIN TO SNOW
OCCURS INTO THE CNTRL AND EASTERN CWA. A COUPLE INCHES OF SNOW MAY
OCCUR WITH THE CHANGE BUT DEFORMATION HINTS FROM THE MODEL QPF
FIELDS NOT AS STRIKING/PERSISTENT. BY LATE TONIGHT...ALL PRECIP WILL
BE IN THE FORM OF SNOW...BUT PRECIP INTENSITY WILL BE ON THE WANE AS
COMMA HEAD OF LOW PRESSURE DIMINISHES. IMPROVING WEATHER ON SUNDAY
WITH LINGERING CLOUDS GIVING WAY TO AFTERNOON SUNSHINE. ONSHORE FLOW
OFF LK SUPERIOR SHOULD KEEP TEMPS ON THE COOL SIDE OVER THE NORTH
HALF. READINGS INTO THE LOWER 40S SEEM REASONABLE IN THE SOUTH WITH
DOWNSLOPING FLOW AND MORE SUNSHINE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 507 PM EDT SAT APR 6 2013
A PATTERN CHANGE STILL APPEARS TO BE IN THE OFFING OVER THE NEXT
COUPLE OF WEEKS THAT SHOULD TRANSITION THE PERSISTENT BELOW NORMAL
TEMP REGIME TOWARD A NORMAL OR ABOVE NORMAL ONE. HOWEVER...
CONFIDENCE IS NOT HIGH THAT ABOVE NORMAL TEMPS WILL ACTUALLY SET IN.
THE AO AND NAO WHICH HAVE BEEN IN A PREVAILING NEGATIVE PHASE SINCE
EARLY/MID FEB ARE STILL BOTH FORECAST TO TREND TO THE POSITIVE PHASE
WHICH SHOULD TRANSLATE TO WARMING. HOWEVER...THE GFS ENSEMBLES ARE
ROUGHLY SPLIT IN EITHER MAINTAINING A WEAK NEGATIVE NAO OR ONLY
GOING TO A SLIGHT POSITIVE PHASE. THE FORECASTED PHASE OF THE MJO
FAVORS BLO NORMAL TEMPS FOR THE UPPER LAKES THRU ABOUT MID MONTH
THEN ABOVE NORMAL LATE MONTH. SO...WHILE TEMPS OVERALL WILL LIKELY
FALL ON THE COLDER SIDE OF NORMAL FOR THE NEXT WEEK OR SO...THE
PROSPECT FOR NORMAL OR ABOVE NORMAL TEMPS SHOULD INCREASE FOR THE
LATTER PART OF APRIL. BOTH THE GFS AND ECMWF ARE SHOWING ANOTHER
TROF SETTLING INTO THE WRN CONUS IN THE 7-10DAY PERIOD...SO THAT MAY
BE THE HARBINGER OF THE POSSIBLE WARMER PATTERN TO FOLLOW...OR AT
LEAST ONE THAT IS MORE VARIABLE RATHER THAN PERSISTENTLY BLO NORMAL.
THE PATTERN WILL ALSO BE AN ACTIVE ONE ACROSS THE CONUS. AFTER
TODAYS SYSTEM AFFECTING THE UPPER LAKES...TROF AMPLIFICATION WILL
OCCUR OVER THE WRN CONUS OVER THE NEXT FEW DAYS WITH THE TROF THEN
SLOWLY TRANSLATING ACROSS THE CONUS DURING THE WEEK. THIS WILL
PROVIDE THE POTENTIAL FOR SIGNIFICANT PCPN EVENTS THRU MUCH OF THE
COMING WEEK FROM THE PLAINS EWD AS THE GULF FULLY OPENS UP. FOR
UPPER MI...THIS COULD MEAN ONE OR MORE UNWELCOMED RAIN EVENTS ON A
MELTING SNOWPACK WHICH IS STILL DEEP IN THE LAKE EFFECT AREAS OR
SIGNIFICANT SNOW COULD STILL BE ADDED. MUCH WILL DEPEND ON THE
STRENGTH OF THE ERN CANADA TROF THAT IS STILL IN PLACE UNDER THE
LINGERING...BUT WEAKENING NEGATIVE AO/NAO REGIME. IF THE TROF
REMAINS STRONG...EPISODES OF HVY PCPN ASSOCIATED WITH THE SLOWLY
PROGRESSIVE SRN STREAM TROF WILL PASS BY TO THE S...LEAVING DRIER
WEATHER TO DOMINATE HERE. WITH THE CONSIDERABLE SNOWPACK STILL IN
PLACE...A DRIER WEATHER REGIME WOULD BE HELPFUL BECAUSE THE LATER WE
GO THRU APRIL ADDING PCPN TO THE SNOWPACK WITHOUT MUCH MELTING
THE GREATER THE POTENTIAL WILL BECOME FOR A RAPID MELTDOWN AND
INCREASED FLOODING. AFTER THE FIRST WRN TROF LIFTS OUT...THE
PROSPECT OF ANOTHER DEVELOPING 7-10 DAYS DOWN THE ROAD IS A CONCERN
AS IT WOULD FAVOR THE POTENTIAL FOR MORE FREQUENT PCPN EVENTS ON THE
MELTING SNOWPACK.
AFTER SIGNIFICANT INCONSISTENCIES FOR SEVERAL DAYS AMONG ALL THE
MEDIUM RANGE GUIDANCE...MODELS ARE NOW ON BOARD WITH AN INITIAL
SHORTWAVE EJECTING INTO THE UPPER LAKES SUN NIGHT/MON AHEAD OF THE
DEVELOPING WRN TROF. WITH PRECIPITABLE WATER VALUES RISING TO
160-200 PCT OF NORMAL...A GOOD PUSH OF ISENTROPIC ASCENT PER 295K
SFC...AND FGEN FORCING UNDER RIGHT ENTRANCE REGION OF UPPER JET...
PCPN APPEARS LIKELY. BASED ON 850MB TEMPS/1000-850MB
THICKNESS...PTYPE SHOULD TRANSITION FROM SNOW OR SNOW/FZRA/RA WHEN
IT BEGINS OVERNIGHT SUN NIGHT TO MOSTLY RAIN DURING MON. THE ONLY
PLACE SOME SNOW MAY STILL MIX WITH RAIN MON AFTN IS OVER THE HIGHER
TERRAIN OF NW UPPER MI. MIGHT SEE A TRANSITION BACK TO SNOW OR A
RAIN/SNOW MIX AS THE PCPN EXITS MON NIGHT.
DURING THE MID AND LATE WEEK PERIOD...WILL LEAN FCST MORE STRONGLY
TOWARD THE ECMWF WHICH HAS NOW DEVELOPED GOOD RUN-TO-RUN CONSISTENCY
OVER THE LAST 5 RUNS WITH REGARD TO THE WRN TROF LIFTING OUT. THE
ECWMF ALSO SEEMS TO BETTER FIT THE PATTERN OF THE LINGERING BUT
WEAKENING NEGATIVE NAO WHICH HOLDS STRONGER TROFFING IN OVER SE
CANADA. IT IS ALSO ENCOURAGING TO SEE THE ONCE VERY INCONSISTENT AND
EXTREME GFS SHIFTING TOWARD SOMETHING MUCH MORE LIKE THE ECMWF (MANY
GFS RUNS SHOWED A STRONG SURGE OF SPRING WARMTH INTO UPPER LAKES
MIDWEEK AS IT TRACKED RATHER DEEP SFC LOWS THRU THE UPPER
MISSISSIPPI VALLEY). THE 00Z UKMET LENDS SUPPORT TO THE ECMWF THOUGH
IT DOES HAVE A STRONGER SFC LOW FARTHER N INTO NRN LWR MI THU IN
RESPONSE TO THE MAIN ENERGY LIFTING NE. THE GEM HAS BECOME MORE
INCONSISTENT...AND ITS 00Z/12Z RUNS APPEAR TOO FAST LIFTING TROF OUT
COMPARED TO OTHER GUIDANCE. SO...WHILE CONFIDENCE IN THE RESULTING
SENSIBLE WEATHER FOR THE FCST AREA IS STILL LOW...IT IS IMPROVED
FROM RECENT DAYS. IN INCORPORATING MORE OF THE ECMWF INTO THE
FCST...EXPECT DRY WEATHER TO PREVAIL TUE WITH SFC HIGH PRES RIDGE
NOSING INTO THE UPPER LAKES FROM THE NW. ALTHOUGH TIMING THE LIFTING
OUT OF THE WRN TROF AND ANY SHORTWAVES WILL CONTINUE TO BE
PROBLEMATIC...WILL SHOW SOME INCREASED POTENTIAL FOR PCPN WED...
MAINLY OVER THE S WHERE LOW CHC POPS WILL BE UTILIZED...BUT MORE SO
THU GIVEN THAT THE LAST 5 ECMWF RUNS HAVE BEEN POINTING TOWARD THU
AS THE DAY THE MAIN PIECE OF ENERGY AFFECTS THE AREA. PTYPE WOULD
PROBABLY BE MAINLY SNOW. GIVEN THE OPEN GULF...THE SNOW COULD BE
SIGNIFICANT...BUT THAT POTENTIAL APPEARS TO BE DIMINISHING AS THE
ECMWF HAS SHOWN A TENDENCY FOR ANY SFC LOWS TO BE WEAKER AND FARTHER
SE DUE TO THE STRONGER TROF AND CONFLUENCE ZONE IT HAS LINGERING
OVER SE CANADA...WHICH AGAIN DOES FIT THE RECENT PATTERN AS ALLUDED
TO ABOVE. THIS RESULTS IN THE BEST PUSH OF MOISTURE/WAA BEING
SUPPRESSED TO THE S AND E. WILL LINGER CHC POPS INTO FRI AS
MID/UPPER LEVEL TROF PASSES AND THEN SHOOT FOR A DRY SAT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 702 PM EDT SAT APR 6 2013
AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE LOW WILL MOVE INTO
THE AREA EARLY THIS EVENING. SNOW WILL CONTINUE WITH LOW
VISIBILITIES AND CIGS AT IWD AND CMX THIS EVENING BEFORE THE
MOISTURE MOVES OUT AND CONDITIONS IMPROVE TO MVFR BY SUN MORNING.
MIXED PRECIPITATION AT SAW WILL TRANSITION TO ALL SNOW WHICH WILL
REDUCE VISIBILITY TO AROUND 1SM LATER THIS EVENING. AS THE LOW
PRESSES EASTWARD LATE TONIGHT THROUGH SUNDAY MORNING EXPECT
VISIBILITY AND CEILINGS TO IMPROVE FIRST AT IWD AND CMX AND LATER AT
KSAW AND BY AFTERNOON...CONDITIONS WILL BE VFR AT ALL SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EDT SAT APR 6 2013
ACROSS LAKE SUPERIOR...SE TO E WINDS OF 15-30KT WILL BACK AROUND TO
THE N/NW TONIGHT IN THE WAKE OF LOW PRES PASSING JUST S OF LAKE
SUPERIOR. THE STRONGEST WINDS TONIGHT THRU SUN MORNING WILL BE OVER
ERN LAKE SUPERIOR. WINDS WILL THEN STEADILY DIMINISH W TO E SUN...
FALLING TO AOB 15KT...AS HIGH PRES RIDGE NOSES INTO THE UPPER LAKES.
AS THE RIDGE DEPARTS...E TO SE WINDS WILL INCREASE A BIT SUN
NIGHT/MON...BUT SHOULD REMAIN UNDER 20KT. TUE-THU...N TO NE WINDS
WILL DOMINATE AS THE UPPER LAKES WILL BE SITUATED BTWN HIGH PRES TO
THE N AND A LOW PRES TROF EXTENDING FROM THE SRN PLAINS TO THE OHIO
VALLEY. AT TIMES...WINDS WILL BE IN THE 15-25KT RANGE...DEPENDING ON
ANY WAVES OF LOW PRES TRACKING ALONG THE TROF TO THE S.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 AM EDT SUNDAY FOR MIZ001-003>005-
084.
WINTER WEATHER ADVISORY UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING
FOR MIZ002-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
508 PM EDT SAT APR 6 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 507 PM EDT SAT APR 6 2013
FIGURING OUT THIS MESSY SPRING SYSTEM CONTINUES TO BE A DIFFICULT
PROPOSITION.
999MB SFC LOW CONTINUES TO TRACK EAST ACROSS MINNESOTA...JUST TO
SOUTH OF TWIN CITIES AS OF 19Z. SFC WARM FRONT WELL TO SOUTH ACROSS
SOUTHERN WI. TEMP OF 60F AT MSN. READINGS NEAR 40F ARE CLOSING IN ON
WI BORDER. REMAINS IN THE LOW-MID 30S ELSEWHERE...COLDEST OVR THE
KEWEENAW PENINSULA AND OUT IN THE FAR EASTERN CWA AROUND KERY.
LARGER SCALE QUITE THE MESS AS THERE ARE MULTIPLE SHORTWAVES AND
MORE OF A SPLIT TROUGH LOOK AT H7-H5. NORTHERN STREAM WAVE IS
STRONGER THAN EXPECTED AND THIS HAS ALLOWED FOR STRONGER H925-H85
TROUGH TO DRAW WARM AIR AT 975-850MB INTO UPR MICHIGAN. CURRENT
RADAR SHOWS INITIAL WARM AIR ADVECTION SNOW IS 1-2 HRS FROM ENDING
AT KERY AND THERE HAS BEEN A DECENT LULL THAT OCCURED THIS AFTN OVR
MUCH OF THE CWA...EXCEPT ACROSS THE KEWEENAW WHERE SNOW HAS BEEN
STEADY MOST OF THE DAY.
UPSTREAM THOSE MULTIPLE SHORTWAVE TROUGHS ARE RESULTING IN MANY
AREAS OF PRECIPITATION. STRONGEST AREA OF PRECIP IS TIED TO
NORTHERN WAVE...WITH WIDESPREAD PRECIPITATION OVER NORTHEAST
MINNESOTA. CLUSTERS OF PRECIP ARE ALSO FILLING IN AHEAD OF SOUTHERN
STREAM WAVE AND SFC LOW OVER ECNTRL MN AND ALONG SFC WARM FRONT OVER
SOUTHERN WI. GRADUALLY THESE TWO SHORTWAVE TROUGHS ARE SHOWN TO PHASE
OVER WI/LK MICHIGAN TONIGHT...ALLOWING PRECIPITATION TO EXPAND OVR
MUCH OF CWA. FOLLOWING 975-950MB TEMPS FROM RUC/NAM/GFS POINTS TO
RAIN BEING DOMINANT PTYPE EARLY THIS EVENING OVER ALL BUT KEWEENAW
PENINSULA. HEAVIER PRECIPITATION MOVING OVER KDLH IN LAST HOUR HAS
PRODUCED RA/FZRA/PL/SN...EVEN AS RUC WARM LAYER WAS WELL ABOVE 0C.
THIS IS CERTAINLY THE DYNAMIC COOLING THAT MODELS WERE HINTING AT
ON FRIDAY. HINTS FROM NAM/GFS AND HRRR...WHICH IS HANDLING CURRENT
PRECIP TRENDS QUITE WELL...THAT SIMILAR SITUATION MAY OCCUR MID-LATE
EVENING OVER WESTERN THIRD OF CWA. TRIED TO SHOW THIS IN PYTPE GRIDS
AND ALSO INCREASED SNOWFALL AMOUNTS INTO 2-4 INCH RANGE FROM IRONWOOD
TO HOUGHTON AND INTO THE HURON MOUNTANS. ELSEWHERE THOUGH LATE EVENING
DO NOT EXPECT MUCH SNOW AT ALL AS WARM AIR ALOFT DOMINATES.
LATE EVENING INTO THE EARLY OVERNIGHT CHANGEOVER FROM RAIN TO SNOW
OCCURS INTO THE CNTRL AND EASTERN CWA. A COUPLE INCHES OF SNOW MAY
OCCUR WITH THE CHANGE BUT DEFORMATION HINTS FROM THE MODEL QPF
FIELDS NOT AS STRIKING/PERSISTENT. BY LATE TONIGHT...ALL PRECIP WILL
BE IN THE FORM OF SNOW...BUT PRECIP INTENSITY WILL BE ON THE WANE AS
COMMA HEAD OF LOW PRESSURE DIMINISHES. IMPROVING WEATHER ON SUNDAY
WITH LINGERING CLOUDS GIVING WAY TO AFTERNOON SUNSHINE. ONSHORE FLOW
OFF LK SUPERIOR SHOULD KEEP TEMPS ON THE COOL SIDE OVER THE NORTH
HALF. READINGS INTO THE LOWER 40S SEEM REASONABLE IN THE SOUTH WITH
DOWNSLOPING FLOW AND MORE SUNSHINE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 507 PM EDT SAT APR 6 2013
A PATTERN CHANGE STILL APPEARS TO BE IN THE OFFING OVER THE NEXT
COUPLE OF WEEKS THAT SHOULD TRANSITION THE PERSISTENT BELOW NORMAL
TEMP REGIME TOWARD A NORMAL OR ABOVE NORMAL ONE. HOWEVER...
CONFIDENCE IS NOT HIGH THAT ABOVE NORMAL TEMPS WILL ACTUALLY SET IN.
THE AO AND NAO WHICH HAVE BEEN IN A PREVAILING NEGATIVE PHASE SINCE
EARLY/MID FEB ARE STILL BOTH FORECAST TO TREND TO THE POSITIVE PHASE
WHICH SHOULD TRANSLATE TO WARMING. HOWEVER...THE GFS ENSEMBLES ARE
ROUGHLY SPLIT IN EITHER MAINTAINING A WEAK NEGATIVE NAO OR ONLY
GOING TO A SLIGHT POSITIVE PHASE. THE FORECASTED PHASE OF THE MJO
FAVORS BLO NORMAL TEMPS FOR THE UPPER LAKES THRU ABOUT MID MONTH
THEN ABOVE NORMAL LATE MONTH. SO...WHILE TEMPS OVERALL WILL LIKELY
FALL ON THE COLDER SIDE OF NORMAL FOR THE NEXT WEEK OR SO...THE
PROSPECT FOR NORMAL OR ABOVE NORMAL TEMPS SHOULD INCREASE FOR THE
LATTER PART OF APRIL. BOTH THE GFS AND ECMWF ARE SHOWING ANOTHER
TROF SETTLING INTO THE WRN CONUS IN THE 7-10DAY PERIOD...SO THAT MAY
BE THE HARBINGER OF THE POSSIBLE WARMER PATTERN TO FOLLOW...OR AT
LEAST ONE THAT IS MORE VARIABLE RATHER THAN PERSISTENTLY BLO NORMAL.
THE PATTERN WILL ALSO BE AN ACTIVE ONE ACROSS THE CONUS. AFTER
TODAYS SYSTEM AFFECTING THE UPPER LAKES...TROF AMPLIFICATION WILL
OCCUR OVER THE WRN CONUS OVER THE NEXT FEW DAYS WITH THE TROF THEN
SLOWLY TRANSLATING ACROSS THE CONUS DURING THE WEEK. THIS WILL
PROVIDE THE POTENTIAL FOR SIGNIFICANT PCPN EVENTS THRU MUCH OF THE
COMING WEEK FROM THE PLAINS EWD AS THE GULF FULLY OPENS UP. FOR
UPPER MI...THIS COULD MEAN ONE OR MORE UNWELCOMED RAIN EVENTS ON A
MELTING SNOWPACK WHICH IS STILL DEEP IN THE LAKE EFFECT AREAS OR
SIGNIFICANT SNOW COULD STILL BE ADDED. MUCH WILL DEPEND ON THE
STRENGTH OF THE ERN CANADA TROF THAT IS STILL IN PLACE UNDER THE
LINGERING...BUT WEAKENING NEGATIVE AO/NAO REGIME. IF THE TROF
REMAINS STRONG...EPISODES OF HVY PCPN ASSOCIATED WITH THE SLOWLY
PROGRESSIVE SRN STREAM TROF WILL PASS BY TO THE S...LEAVING DRIER
WEATHER TO DOMINATE HERE. WITH THE CONSIDERABLE SNOWPACK STILL IN
PLACE...A DRIER WEATHER REGIME WOULD BE HELPFUL BECAUSE THE LATER WE
GO THRU APRIL ADDING PCPN TO THE SNOWPACK WITHOUT MUCH MELTING
THE GREATER THE POTENTIAL WILL BECOME FOR A RAPID MELTDOWN AND
INCREASED FLOODING. AFTER THE FIRST WRN TROF LIFTS OUT...THE
PROSPECT OF ANOTHER DEVELOPING 7-10 DAYS DOWN THE ROAD IS A CONCERN
AS IT WOULD FAVOR THE POTENTIAL FOR MORE FREQUENT PCPN EVENTS ON THE
MELTING SNOWPACK.
AFTER SIGNIFICANT INCONSISTENCIES FOR SEVERAL DAYS AMONG ALL THE
MEDIUM RANGE GUIDANCE...MODELS ARE NOW ON BOARD WITH AN INITIAL
SHORTWAVE EJECTING INTO THE UPPER LAKES SUN NIGHT/MON AHEAD OF THE
DEVELOPING WRN TROF. WITH PRECIPITABLE WATER VALUES RISING TO
160-200 PCT OF NORMAL...A GOOD PUSH OF ISENTROPIC ASCENT PER 295K
SFC...AND FGEN FORCING UNDER RIGHT ENTRANCE REGION OF UPPER JET...
PCPN APPEARS LIKELY. BASED ON 850MB TEMPS/1000-850MB
THICKNESS...PTYPE SHOULD TRANSITION FROM SNOW OR SNOW/FZRA/RA WHEN
IT BEGINS OVERNIGHT SUN NIGHT TO MOSTLY RAIN DURING MON. THE ONLY
PLACE SOME SNOW MAY STILL MIX WITH RAIN MON AFTN IS OVER THE HIGHER
TERRAIN OF NW UPPER MI. MIGHT SEE A TRANSITION BACK TO SNOW OR A
RAIN/SNOW MIX AS THE PCPN EXITS MON NIGHT.
DURING THE MID AND LATE WEEK PERIOD...WILL LEAN FCST MORE STRONGLY
TOWARD THE ECMWF WHICH HAS NOW DEVELOPED GOOD RUN-TO-RUN CONSISTENCY
OVER THE LAST 5 RUNS WITH REGARD TO THE WRN TROF LIFTING OUT. THE
ECWMF ALSO SEEMS TO BETTER FIT THE PATTERN OF THE LINGERING BUT
WEAKENING NEGATIVE NAO WHICH HOLDS STRONGER TROFFING IN OVER SE
CANADA. IT IS ALSO ENCOURAGING TO SEE THE ONCE VERY INCONSISTENT AND
EXTREME GFS SHIFTING TOWARD SOMETHING MUCH MORE LIKE THE ECMWF (MANY
GFS RUNS SHOWED A STRONG SURGE OF SPRING WARMTH INTO UPPER LAKES
MIDWEEK AS IT TRACKED RATHER DEEP SFC LOWS THRU THE UPPER
MISSISSIPPI VALLEY). THE 00Z UKMET LENDS SUPPORT TO THE ECMWF THOUGH
IT DOES HAVE A STRONGER SFC LOW FARTHER N INTO NRN LWR MI THU IN
RESPONSE TO THE MAIN ENERGY LIFTING NE. THE GEM HAS BECOME MORE
INCONSISTENT...AND ITS 00Z/12Z RUNS APPEAR TOO FAST LIFTING TROF OUT
COMPARED TO OTHER GUIDANCE. SO...WHILE CONFIDENCE IN THE RESULTING
SENSIBLE WEATHER FOR THE FCST AREA IS STILL LOW...IT IS IMPROVED
FROM RECENT DAYS. IN INCORPORATING MORE OF THE ECMWF INTO THE
FCST...EXPECT DRY WEATHER TO PREVAIL TUE WITH SFC HIGH PRES RIDGE
NOSING INTO THE UPPER LAKES FROM THE NW. ALTHOUGH TIMING THE LIFTING
OUT OF THE WRN TROF AND ANY SHORTWAVES WILL CONTINUE TO BE
PROBLEMATIC...WILL SHOW SOME INCREASED POTENTIAL FOR PCPN WED...
MAINLY OVER THE S WHERE LOW CHC POPS WILL BE UTILIZED...BUT MORE SO
THU GIVEN THAT THE LAST 5 ECMWF RUNS HAVE BEEN POINTING TOWARD THU
AS THE DAY THE MAIN PIECE OF ENERGY AFFECTS THE AREA. PTYPE WOULD
PROBABLY BE MAINLY SNOW. GIVEN THE OPEN GULF...THE SNOW COULD BE
SIGNIFICANT...BUT THAT POTENTIAL APPEARS TO BE DIMINISHING AS THE
ECMWF HAS SHOWN A TENDENCY FOR ANY SFC LOWS TO BE WEAKER AND FARTHER
SE DUE TO THE STRONGER TROF AND CONFLUENCE ZONE IT HAS LINGERING
OVER SE CANADA...WHICH AGAIN DOES FIT THE RECENT PATTERN AS ALLUDED
TO ABOVE. THIS RESULTS IN THE BEST PUSH OF MOISTURE/WAA BEING
SUPPRESSED TO THE S AND E. WILL LINGER CHC POPS INTO FRI AS
MID/UPPER LEVEL TROF PASSES AND THEN SHOOT FOR A DRY SAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 137 PM EDT SAT APR 6 2013
AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE LOW WILL MOVE INTO
THE AREA FROM SOUTHERN MN THIS AFTERNOON THROUGH TONIGHT. SLIGHTLY
WARMER TEMPERATURES ARE MOVING IN ALOFT ALLOWING THE SNOW TO MIX
AND IN SOME CASES CHANGE TO RAIN AS SUPPORTED BY RADAR AND SURFACE
OBSERVATIONS UP STREAM...WHICH WILL HELP TO INCREASE VISIBILITY
SLIGHTLY THIS AFTERNOON. EXPECT THIS TREND TO CONTINUE AT ALL TAF
SITES THIS AFTERNOON BEFORE SLOWLY TRANSITIONING TO SNOW FROM WEST
TO EAST OVERNIGHT. THIS TRANSITION TO ALL SNOW WILL REDUCE
VISIBILITY TO AROUND 1SM WITH CMX AND IWD POSSIBLY GOING TO 1/2SM
WITH THE HEAVIER SNOW BANDS THIS EVENING. AS THE TROUGH MOVES
OVERHEAD TONIGHT EXPECT CEILINGS TO DROP TO IFR OVER KSAW
OVERNIGHT...WHILE IWD AND CMX REMAIN AT IFR OR LOWER THROUGH THE
OVERNIGHT HOURS. AS THE LOW PRESSES EASTWARD LATE TONIGHT THROUGH
SUNDAY MORNING EXPECT VISIBILITY AND CEILINGS TO IMPROVE FIRST AT IWD
AND CMX AND LATER AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EDT SAT APR 6 2013
ACROSS LAKE SUPERIOR...SE TO E WINDS OF 15-30KT WILL BACK AROUND TO
THE N/NW TONIGHT IN THE WAKE OF LOW PRES PASSING JUST S OF LAKE
SUPERIOR. THE STRONGEST WINDS TONIGHT THRU SUN MORNING WILL BE OVER
ERN LAKE SUPERIOR. WINDS WILL THEN STEADILY DIMINISH W TO E SUN...
FALLING TO AOB 15KT...AS HIGH PRES RIDGE NOSES INTO THE UPPER LAKES.
AS THE RIDGE DEPARTS...E TO SE WINDS WILL INCREASE A BIT SUN
NIGHT/MON...BUT SHOULD REMAIN UNDER 20KT. TUE-THU...N TO NE WINDS
WILL DOMINATE AS THE UPPER LAKES WILL BE SITUATED BTWN HIGH PRES TO
THE N AND A LOW PRES TROF EXTENDING FROM THE SRN PLAINS TO THE OHIO
VALLEY. AT TIMES...WINDS WILL BE IN THE 15-25KT RANGE...DEPENDING ON
ANY WAVES OF LOW PRES TRACKING ALONG THE TROF TO THE S.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MIZ007.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT SUNDAY FOR MIZ001-003>005-
084.
WINTER WEATHER ADVISORY UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING
FOR MIZ002-009.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...KEC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
155 PM EDT SAT APR 6 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT SAT APR 6 2013
SHOWERS WILL INCREASE BY LATE AFTERNOON AS A LOW PRESSURE SYSTEM
APPROACHES THE AREA. THE STEADIEST RAINS ARE EXPECTED THIS EVENING
AS THE LOW AND A COLD FRONT TRACKS THROUGH THE GREAT LAKES. A
RUMBLE OF THUNDER IS ALSO POSSIBLE THIS EVENING. THE RAIN WILL END
OR BECOME WIDELY SCATTERED LATE TONIGHT. AFTER A QUIET
SUNDAY...MORE RAIN CAN BE EXPECTED LATE SUNDAY NIGHT INTO MONDAY.
DAYTIME HIGH TEMPERATURES WILL MAINLY BE IN THE 50S TODAY THROUGH
MONDAY...ALTHOUGH A FEW LOCALES COULD HIT THE 60 DEGREE MARK TODAY
AND AGAIN ON MONDAY.
MORE RAIN IS IN STORE FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
&&
.UPDATE...
ISSUED AT 1138 AM EDT SAT APR 6 2013
THE THREAT OF LIGHT SNOW OR MIXED RAIN AND SNOW NORTH OF I 96 IS
ENDING AS WARM FRONTAL PRECIP LIFTS OUT OF THE AREA AND SFC TEMPS
WARM THROUGH THE 40S. THE MAIN STORY NOW FOR THE REST OF THE DAY
IS BREEZY CONDITIONS WITH RISING TEMPS. WARMEST HIGH TEMPS... IN
THE LOWER 60S... SHOULD BE IN THE SW CORNER OF THE CWFA.
MEANWHILE THE NE CORNER NEAR CLARE MAY STRUGGLE TO HIT 50.
UPDATE ISSUED AT 726 AM EDT SAT APR 6 2013
BASED ON THE RADAR AND SURFACE OBSERVATIONS NOW SHOWING
PRECIPITATION REACHING THE GROUND FROM MKG TO LDM... RAIN AT MKG
AND LIGHT SNOW AT LDM... PLUS CONSIDERING THE LATEST RUNS OF THE
RAP ARW HRRR MODELS I INCREASED POPS OVER THE NORTHERN CWA INTO
MID MORNING. I ALSO USED THE HRRR TO UPDATE THE TEMP AND WIND
GRIDS... THIS GIVES WARMER AFTERNOON TEMPERATURES AND HIGHER WIND
GUSTS. GIVEN THE LATEST NAM12 1000 TO 925 MB THICKNESS VALUES THE
HRRR HIGHER MAX TEMPS (NEAR 60 SOUTH OF INTERSTATE 96) MAKE SENSE.
THAT WILL ENABLE DEEPER MIXING AND HIGHER WIND GUSTS TOO.
STILL LOOKS GOOD FOR SOME ISOLATED THUNDERSTORMS CROSSING LAKE
MICHIGAN INTO SOUTHWEST LOWER MICHIGAN (SPC 03Z SREF/NAM12 MAX
CAPE) IN THE 8 PM TO MIDNIGHT TIME FRAME. SEEMS IT WILL MOST BE
SOUTH OF MKG AND WEST OF US-131.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM EDT SAT APR 6 2013
HIGH PRESSURE WAS SLIPPING OFF TO THE EAST THIS MORNING. A WARM
FRONT WAS MOVING NORTHWARD ACROSS IL...ATTACHING TO LOW PRESSURE
OVER SE SD.
LOOKS LIKE WE WILL GET A SHORT BURST OF WARM ADVECTION PCPN THIS
MORNING. THIS WILL BE DRIVEN BY A LOW LEVEL JET WHICH WILL BE
INTERSECTING THE WARM FRONT. THE PCPN WILL BE MAINLY SNOW NE OF
GRR...ALTHOUGH ACCUMS SHOULD ONLY BE A LIGHT DUSTING BEFORE ANY PCPN
CHANGES TO ALL RAIN LATE THIS MORNING. ONCE THIS PCPN MOVES THROUGH
WE SHOULD SEE A LULL IN THE PCPN MID DAY...ALTHOUGH A FEW SHOWERS
MAY LINGER FAR NORTH. THEN AS THE SURFACE COLD FRONT AND LOW
APPROACHES THE RAIN SHOULD BECOME STEADIER AND MORE WIDESPREAD AFTER
21Z TODAY FROM NW TO SE. TEMPS ACROSS THE CWA...NE AREAS JUST
REACHING AROUND 50...WHILE SW AREAS SHOULD REACH AROUND 60 AS THIS
AREA WILL BE IN THE WARM SECTOR OF AWHILE TODAY.
THE BULK OF THE RAIN SHOULD COME THIS EVENING...AHEAD OF THE FROPA.
STILL ENOUGH INSTABILITY AND CAPE NEAR THE FRONT TO MAINTAIN THE
MENTION OF THUNDER FOR ALL OF THE CWA. STEADIEST RAINS SHOULD BE
OVER THE NORTHERN CWA...CLOSEST TO THE SURFACE LOW WHERE A QUARTER A
HALF INCH OF RAIN SHOULD OCCUR. MOST AREAS SOUTH AND EAST OF GRR
SHOULD SEE LESS THAN A QUARTER INCH.
THE FORECAST OF A DRY SUNDAY STILL LOOKS GOOD WITH WEAK SURFACE AND
UPPER RIDGING MOVING IN. HOW QUICKLY WE WILL CLEAR WILL MAKE FOR A
TOUGH TEMP FORECAST. ENOUGH SUN COULD PUSH TEMPS WELL INTO THE
50S...OR IF THE CLOUDS WERE TO LINGER WE MAY STRUGGLE TO REACH 50.
WILL GO OPTIMISTICALLY AS CLEARING LOOKS FAIRLY LIKELY BY AFTERNOON
AND WILL RAISE MAX TEMPS.
WILL ADD SOME TIMING IN THE GRIDS FOR SUNDAY NIGHT AS THE PCPN
SHOULD ARRIVE AFTER MIDNIGHT. THE MOISTURE DOES NOT RETURN UNTIL
THEN AND THE FORCING REMAINS WEAK THROUGH THE EVENING. HOWEVER
AFTER MIDNIGHT A WARM FRONT WILL SLOWLY LIFT NORTH ACROSS NRN
INDIANA AND SPREAD DEEPER MOISTURE INTO LOWER MI. UPPER DIVERGENCE
FROM THE RIGHT ENTRANCE REGION OF A JET WILL MOVE IN BETWEEN 06Z AND
12Z AND AREAS ALONG AND SOUTH OF I-96 SHOULD SEE RAIN DEVELOP.
FORCING CONTINUES INTO MONDAY AND SPREADS NORTH ACROSS ALL OF THE
CWA. THE WARM FRONT SHOULD MOVE NORTH INTO SOUTHERN SECTIONS OF THE
CWA. THIS WILL MAKE FOR ANOTHER TOUGH TEMP FORECAST. EXPECT AREAS
SOUTH OF THE FRONT WILL GET WELL INTO THE 60S...WHILE HOLDING IN THE
50S NORTH OF THE FRONT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT APR 6 2013
WE CONTINUE TO MONITOR THE POTENTIAL FOR A SIGNIFICANT RAIN...
FREEZING RAIN OR THUNDERSTORM EVENT IN THE WEDNESDAY TIME FRAME AS
THE ENERGY FROM THE SOUTHERN STREAM SYSTEM IS BOOTED OUT INTO THE
CENTRAL PLAINS AND GREAT LAKES. THE ISSUE IS IF THE ECMWF OR THE GFS
IS CORRECT ON THE TRACK OF THE SYSTEM.
AS HAS BEEN TRUE AND TO THIS POINT CONTINUES TO BE TRUE IS THE ECMWF
CONTINUES TO TRACK THE WED SYSTEM SOUTH OF LOWER MICHIGAN. THAT
KEEPS THE BEST INSTABILITY AND STRONGER THUNDERSTORMS SOUTH OF
MICHIGAN TOO. HOWEVER WE WOULD GET A DECENT OVERRUNNING RAIN EVENT IF
THE ECMWF TURNS OUT TO BE CORRECT. IT SHOULD BE NOTED THAT FOR 4
RUNS OF THE GFS IN A ROW THE WEDNESDAY SYSTEM IS FARTHER SOUTH ON
EACH RUN. FOR EXAMPLE... THE 05TH 06Z RUN OF THE GFS VALID AT 00Z ON
THE 11TH HAD THE SURFACE LOW OVER LAKE SUPERIOR.... BY THE 06TH AT
00Z THAT SAME SYSTEM IS NOW FORECAST OVER SOUTHERN LAKE MICHIGAN BY
THE GFS. THIS SUGGESTS TO ME THE ECMWF WILL TURN OUT TO BE CORRECT
WITH THE MORE SOUTHERLY TRACK OF THE SYSTEM. AS A RESULT OF THAT WE
CONTINUE TO FEATURE COLDER SURFACE TEMPERATURES TUESDAY THROUGH
THURSDAY.
ANOTHER ASPECT OF THE MORE SOUTHERLY TRACK OF THE ECMWF WEDNESDAY IS
THE COLD AIR BRINGING THE POTENTIAL FOR A FREEZING RAIN EVENT TO THE
CENTRAL AND NORTHERN CWA. THE ECMWF HAS SURFACE TEMPERATURES NEAR
FREEZING NEAR AND NORTH OF INTERSTATE 96 DURING THE DAY TIME HOURS
OF WEDNESDAY. GIVEN THE FEED OF CANADIAN POLAR AIR INTO THE AREA IF
THE ECMWF...WHEN YOU CONSIDER THE STEADY PRECIPITATION FALLING ALL
DAY WEDNESDAY THAT MAY WELL BE TRUE. IF THAT IS TRUE WE COULD SEE A
FREEZING RAIN EVENT WEDNESDAY. I DID NOT PLAY THIS SCENARIO IN THE
GRIDS BUT WE WILL HAVE TO WATCH THIS AS IT COULD BE THE MOST
SIGNIFICANT ASPECT OF THIS STORM FOR SOUTHWEST MICHIGAN.
THE ECMWF IS SLOWER TO MOVE THE SYSTEM OUT OF THE AREA... SO THE
PRECIPITATION WOULD CONTINUE INTO FRIDAY BUT FOR NOW I DID NOT SHOW
MUCH PRECIPITATION FRIDAY. WE CAN ADD THAT AS THE TIME GETS CLOSER.
OTHER THAN THAT ALL THE MODELS AGREE THE SYSTEM ON MONDAY WILL BE
DEPARTING THE AREA MONDAY EVENING BUT THE ECMWF CONTINUES TO SHOW
THE CANADIAN SURFACE HIGH BUILDING MORE STRONGLY SOUTH INTO THE
GREAT LAKES TUESDAY. THAT IN TURN PUSHES THE FRONT FARTHER SOUTH
THAN ON THE GEM OR GFS. THAT WOULD LIMIT THE NORTHWARD EXTENT OF
RAINFALL TUESDAY SO I TRIMMED THE POP LOWER OVER OUR NORTHERN CWA TO
ACCOUNT OF THAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 155 PM EDT SAT APR 6 2013
FIRST ROUND OF LIGHT PCPN HAS MOVED THROUGH THE NRN TERMINALS THIS
MORNING. THE ENTIRE AREA IS IN A LULL OF THE PCPN NOW WITH MAINLY
MID CLOUD COVER IN PLACE. ANOTHER BAND OF RAIN IS CURRENTLY OVER
LAKE MICHIGAN AND IS MOVING TO THE NE. THIS SHOULD MAINLY AFFECT
KMKG FOR THIS AFTERNOON...WHILE THE OTHER TERMINALS CONTINUE WITH
JUST MID CLOUDS. WIND GUSTS WILL REMAIN UP AROUND 25 KNOTS OR SO
THROUGH THIS EVENING.
THE MAIN BATCH OF RAIN IS EXPECTED TO DEVELOP LATE THIS AFTERNOON
AND BEGIN MOVING IN ACROSS THE AREA FROM THE WEST JUST BEFORE 00Z.
THIS WILL SPREAD EAST THEN THROUGH THE EVENING...BEFORE ENDING
OVERNIGHT WITH THE PASSAGE OF THE COLD FRONT. LOWER CLOUDS BASED
AROUND 1500 FT ARE EXPECTED TO FOLLOW THE FRONT. THESE CLOUDS
SHOULD LIFT LATE SUN MORNING/SUN AFTERNOON AS THINGS DRY OUT AND
WE MIX THE MOISTURE OUT.
&&
.MARINE...
ISSUED AT 1155 AM EDT SAT APR 6 2013
SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR THE ENTIRE NEARSHORE
AREA. WHILE THE SOUTH FLOW WILL RESULT IN LOWER WAVE HEIGHTS
SOUTH OF HOLLAND AS COMPARED TO AREAS NORTH OF HOLLAND... THE
MAGNITUDE OF THE WIND UP TO 30 KNOTS TODAY STILL MEETS SMALL CRAFT
ADVISORY CRITERIA.
WINDS AND WAVES SHOULD DIMINISH TOWARD MID DAY SUNDAY WITH RIDGING
MOVING IN.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT SAT APR 6 2013
TWO PERIODS OF RAIN IN THE SHORT TERM. IN BOTH CASES THE STEADIEST
RAINS ARE EXPECTED MAINLY NORTHWEST OF A MOP-BIV LINE. UP TO A HALF
INCH OF RAIN CAN BE EXPECTED NORTH OF THIS LINE THROUGH TONIGHT...
AND THEN AGAIN LATE SUNDAY NIGHT INTO MONDAY. AREAS SOUTHEAST OF
THE LINE SHOULD SEE LESS THAN A QUARTER INCH THROUGH TONIGHT...THEN
BETWEEN A QUARTER AND HALF INCH INTO MONDAY.
WE HAVE BEEN RATHER DRY OF LATE SO THE RIVER SHOULD BE ABLE HANDLE
THIS PCPN WITH ONLY MINOR RISES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON EDT SUNDAY FOR LMZ844>849.
&&
$$
UPDATE...MEADE
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...NJJ
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
143 PM EDT SAT APR 6 2013
.UPDATE...
ISSUED AT 1118 AM EDT SAT APR 6 2013
SYSTEM WAS EXPECTED TO BE COMPLICATED...AND IT IS. 999MB SFC LOW
NEAR SIOUX FALLS SD AT 15Z. INITIAL BATCH OF WARM AIR ADVECTION SNOW
HAS BEEN LIGHTER THAN EXPECTED...AND NOW THE WARM AIR IS POISED TO
SWEEP NORTH AHEAD OF STRONGER/FARTHER NORTH 925-850MB LOWS OVER
MINNESOTA. MENTIONED MORE RAIN TODAY...ESPECIALLY IN THE WEST AS
950MB TEMPS CLIMB TOWARD +3C BY 18Z. ALREADY RECEIVING REPORTS JUST
WEST OF CWA OF ONLY RAIN. MAY NEED TO INCLUDE FZRA TOO AS SFC TEMPS
ARE STILL IN THE UPR 20S TO AROUND 30 DEGREES. JUST RECEIVED REPORT
OF SOME FREEZING RAIN MIXING WITH SNOW ON THE KEWEENAW. UPSTREAM
THERE IS NOT MUCH IN WAY OF PRECIPITATION FOR NEXT FEW HOURS.
YET...THERE IS INCREASING ECHOES/REPORTS OF PCPN OVER NORTHERN INTO
NORTHEAST MINNESOTA IN THE LAST TWO HOURS. THIS AREA OF PRECIPITATION
SHOULD SLIDE ACROSS WESTERN/NORTHWEST CWA THIS AFTN. ELSEWHERE...EXPECT
STEADY LIGHT SNOW TO SHIFT STEADILY EAST AND THEN TAPER OFF TO SCT
RAIN/SNOW SHOWERS THROUGH THE AFTN. ONLY RAIN EXPECTED OVER MUCH OF
SOUTHWEST AND SOUTH CNTRL AND...BASED ON 950MB TEMPS +1C TO +2C WITH
LACK OF LARGE SCALE LIFTING/DYNAMIC COOLING PROCESSES...MAYBE AS FAR
NORTH AS BARAGA/MARQUETTE/ALGER COUNTIES AS WELL AFTER MID AFTN.
STEADIER PRECIP THEN MAKES IT INTO CNTRL CWA TOWARD 21Z...WHICH MAY
RESULT IN MIX OF RAIN/SNOW...ESPECIALLY OVER HIGHER TERRAIN OF BARAGA
AND MARQUETTE COUNTIES.
COULD GET INTERESTING TONIGHT OVER THE WEST. H5 SHORTWAVE TROUGH TO
WEST THIS MORNING WAS SPLIT INTO TWO MAIN SECTIONS...ONE OVR
NORTHERN MINNESOTA TIED INTO MAIN H7 TROUGH...AND THE OTHER OVR
PUSHING ACROSS SOUTHEAST SD/SOUTHWEST MN. NORTHERN WAVE IS DRIVING
PRECIP OVER NORTHERN MN AND THEN AS SOUTHERN WAVE CATCHES UP TO THIS
WAVE THIS EVENING...THERE IS INDICATIONS DEFORMATION BAND OF PRECIP
WILL QUICKLY TAKE SHAPE OVER WESTERN UPR MICHIGAN. PTYPE A CONCERN
BUT ONLY INITIALLY AS STRENGTH OF DEFORMATION AND COOLING DUE TO
NORTHERN WAVE SHOULD CHANGE ANY RAIN OVER TO SNOW RATHER QUICKLY.
HRRR/RUC13/NAM ALL SHOW SIMILAR IDEA OF A 2-4 HR PERIOD OF HEAVIER
QPF. FOR THIS REASON...WILL KEEP GOING ADVY EVEN THOUGH MAIN PTYPE
TODAY WILL BE RAIN. OTHERWISE...EXTENT/TIMING OF REMAINDER
ADVISORIES LOOK GOOD BASED ON CURRENT RADAR TRENDS AND/OR EXPECTED
CHANGEOVER TO RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 610 AM EDT SAT APR 6 2013
VERY...VERY COMPLICATED FORECAST WITH ONGOING CHANGES IN THE MODEL
PRECIPITATION LOCATION/AMOUNTS/TYPES.
CURRENTLY...HIGH PRESSURE IS EXITING LOWER MICHIGAN WHILE A 998MB
LOW PRESSURE SYSTEM IS LOCATED IN SOUTHEAST SD. BETWEEN THESE TWO
FEATURES...BROAD LOW-MID LEVEL WARM AIR ADVECTION HAS LEAD TO LIGHT
TO OCCASIONALLY MODERATE SNOW SHOWERS OVER NORTHWEST WISCONSIN AND
MINNESOTA...WHICH HAS SHIFTED INTO SOUTHWESTERN UPPER MICHIGAN OVER
THE LAST COUPLE OF HOURS. DRY LOW LEVEL AIR SEEN ON 00Z KGRB/KINL
SOUNDINGS SEEMS TO HAVE BEEN LIMITING THE INTENSITY OF THE SNOW
THUS FAR...WITH MOST SITES REPORTING VISIBILITIES IN THE 1.5-3MI
RANGE.
THIS FIRST WAVE OF SNOW WILL CONTINUE TO THE EAST-NORTHEAST THROUGH
THE MORNING HOURS AND WITH THE UNDERWHELMING NATURE THUS FAR...IT
SEEMS THE LATEST MODEL TRENDS ARE ON TRACK. EVEN THOUGH THERE IS
PERSISTENT 925-700MB WAA/FGEN AREA THIS MORNING...THE DRY AIR
WILL KEEP SNOW AMOUNTS IN THE 1-3 INCH RANGE AT THE MOST AS THIS
AREA OF SNOW MOVES THROUGH...WITH MOST LOCATIONS SEEING AMOUNTS ON
THE LOW END OF THAT. THERE ARE A FEW CONVECTIVE LOOKING SNOW
SHOWERS FARTHER TO THE SOUTHWEST IN CENTRAL WI/MN THAT HAVE
DEVELOPED OVER THE LAST COUPLE HOURS. THESE MAY HELP FILL IN SOME
OF THE LIGHTER SNOW AREAS...BUT THE COVERAGE WILL LIKELY BE
LIMITED.
THE MORE QUESTIONABLE AND UNCERTAIN PORTION OF THE FORECAST COMES
THIS AFTERNOON INTO TONIGHT...ALTHOUGH LATEST RUNS SEEM TO HAVE THE
SAME IDEA ON A MORE NORTHERLY TRACK TO THE LOW. WV IMAGERY SHOWING
THE MAIN SHORTWAVE WITH THE LOW CURRENTLY ENTERING WESTERN SOUTH
DAKOTA WHILE THE LOW IS IN EASTERN SD. AS THESE TWO FEATURES COME
TOGETHER...EXPECT THE LOW TO INTENSIFY AND LIFT TO THE EAST
NORTHEAST INTO CENTRAL/NORTHERN WI LATE THIS AFTERNOON AND THEN
ACROSS THE MACKINAC STRAITS AROUND 06Z AND JUST NORTH OF THE
GEORGIAN BAY BY 12Z SUNDAY. ALL MODELS NOW HAVE THE IDEA OF WARMER
AIR PUSHING FARTHER NORTH INTO UPPER MICHIGAN THIS AFTERNOON AND
EVENING...AS THE NEXT SWATH OF PRECIPITATION DEVELOPS ON THE NORTH
AND NORTHWEST SIDE OF THE INTENSIFYING LOW. THE FIRST QUESTION MARK
IS IF THERE WILL BE ENOUGH MOISTURE TO LEAD TO PRECIPITATION
REDEVELOPING OVER THE CENTRAL CWA THIS AFTERNOON. WITH THE FIRST
AREA OF PRECIPITATION BECOMING ORIENTATED WEST-EAST ACROSS CENTRAL
LAKE SUPERIOR...THE PERSISTENT WAA FROM 925-700MB AND INCREASING
MOISTURE FROM THE APPROACHING LOW SHOULD LEAD TO SOME SHOWER
REDEVELOPMENT. THE QUESTION IS WHAT TYPE THE PRECIPITATION WILL BE.
WITH THE INCREASING WARM AIR AT THE LOW LEVELS...COULD SEE IT BEING
RAIN OR SNOW OVER THE NORTH HALF OF THE CWA AND RAIN FARTHER SOUTH.
THE LOCATIONS WITH THE MOST WORRIES FOR ACCUMULATIONS WILL BE FROM
THE HIGHER TERRAIN OF MARQUETTE/BARAGA COUNTIES WEST TO GOGEBIC. IN
THIS AREA...BOTH THE COMBINATION OF SURFACE TEMPS IN THE MID 30S
AND A NEARLY ISOTHERMAL TEMPERATURES FOR THE LAST 3-5KFT AROUND 1C
CAUSE CONCERN. JUST A SLIGHT VARIATION IN TEMPERATURES COULD PUSH
PRECIP TO ALL RAIN OR ALL SNOW. WITH THE WARMER TEMPS NEAR THE
SURFACE...HAVE TRENDED MORE TOWARDS A RAIN/SNOW MIX AND EVENTUALLY
TO MOSTLY RAIN AROUND 00Z WHEN THE PEAK WARM AIR IS OVER THE WEST.
SNOW ACCUMULATIONS THEN BECOME A CONCERN...AS THE TEMPS WOULD LIMIT
ACCUMULATION BUT HEAVIER BURSTS COULD PRODUCE A QUICK INCH. FARTHER
TO THE NORTH...EXPECT IT TO MAINLY BE SNOW OVER THE KEWEENAW
PENINSULA.
AS THE LOW TRANSITIONS ENE THROUGH WI AND TOWARDS THE STRAITS OF
MACKINAC TONIGHT...EXPECT A STRONGER AREA OF PRECIPITATION JUST
NORTH OF THE LOW LATE THIS AFTERNOON THROUGH THE EVENING HOURS.
WITH THE WARM AIR EXPECTED IN PLACE OVER THE CENTRAL AND
EAST...WOULD THINK MOST OF THE PRECIP WOULD BE RAIN UNTIL LATE IN
THE NIGHT. OVER THE WEST CENTRAL...SNOWFALL AMOUNTS LARGELY DEPEND
ON TRANSITION TIMING. AN HOUR OR TWO DIFFERENCE COULD MEAN A
SEVERAL INCH DIFFERENCE IN SNOWFALL...AND HAVE WENT ON THE
CONSERVATIVE SIDE WITH ANOTHER 1-3IN TONIGHT FROM THE HIGHER
TERRAIN OF MARQUETTE COUNTY AND WEST. 21Z/03Z SREF PROBABILITIES
AGREE WITH THIS ASSESSMENT OF A BETTER CHANCE OF RAIN BY 00Z AND
THEN CHANGING TO SNOW FROM WEST TO EAST...SO HAVE DEFINITELY
TRENDED THE FORECAST IN THAT DIRECTION. BEHIND THE LOW...900-875MB
TEMPS FALLING TO AROUND -7C LEADS TO ENOUGH LAKE INSTABILITY TO
PRODUCE LAKE ENHANCED SNOWFALL OVER THE NORTHWEST FAVORED LOCATIONS
OVER WESTERN UPPER MICHIGAN AFTER MIDNIGHT AND INTO THE OVERNIGHT
HOURS...BEFORE THE DEEPER MOISTURE QUICKLY DEPARTS FROM WEST TO EAST
AND QUICKLY LOWERS INVERSION HEIGHTS TO 3KFT BY 12Z ON SUNDAY.
ONE INTERESTING ITEM IS THE AMOUNT OF WARM AIR THAT THE LATEST RAP
RUNS PUSH INTO THE AREA. IT HAS KMNM REACHING THE LOWER 50S AND
KIMT/KESC IN THE MID 40S AND EVEN SOME OF KIWD TO KSAW NEARING 40
DEGREES. THIS MAY NOT BE TOO CRAZY...WITH LIMITED DEEP MOISTURE
FARTHER TO THE SOUTHWEST WITH MAINLY MID/HIGH CLOUDS OVER SOUTHERN
WI AND SOUTHERN MN. THIS WOULD LEAD TO A FILTERED SUNSHINE AND
ALLOW MORE HEATING TO REACH THE AREA. HAVE ADJUSTED TEMPS UP SOME
FOR TODAY TO ACCOUNT FOR THIS...BUT NOT AS HIGH AS THE RAP IS
INDICATING.
SO...WHAT TO DO WITH THE HEADLINES. WILL LEAVE THE ADVISORIES AS IS
FOR THE MORNING HOURS DUE TO THE SNOW MOVING INTO THE
AREA...ALTHOUGH THERE IS A GOOD CHANCE MANY LOCATIONS WON/T SEE
ADVISORY TOTALS. FOR AREAS OVER THE SOUTH CENTRAL AND EAST...MOVED
UP ENDING TIME TO MATCH WHEN INITIAL SNOW IS DONE AND EXPECTED
CHANGE OVER TO RAIN. OVER THE WEST...THERE WAS ENOUGH UNCERTAINTY
TO LEAVE THEM AS IS...ALTHOUGH DID EXTEND THE TIME TO BE A LITTLE
LATER. NRN HOUGHTON AND KEWEENAW IS ONE AREA WHERE THERE IS SOME
CONCERN FOR WARNING SNOW AMOUNTS DUE TO THEM STAYING MAINLY SNOW
AND THE INITIAL WAA PRECIPITATION PIVOTING THERE THIS
AFTERNOON/EVENING. ONLY ABOUT 5-6 21Z SREF MEMBERS THAT GET SNOWFALL
AMOUNTS OVER 6IN IN THAT AREA THROUGH TONIGHT. WITH DAYTIME
HEATING LIKELY LIMITING AMOUNT OF ACCUMULATION ON ROADWAYS AND
LIMITED CONFIDENCE ON 6IN...WILL LEAVE AT ADVISORY FOR NOW ALTHOUGH
DAY SHIFT WILL NEED TO MONITOR TRENDS AND POTENTIALLY UPGRADE TO
WARNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 610 AM EDT SAT APR 6 2013
MODELS STILL EXHIBIT GREAT VARIABILITY AND UNCERTAINTY FOR THE
EXTENDED PERIOD OF THE FCST. MUCH OF UNCERTAINTY HINGES ON THE
STRENGTH OF THE LINGERING ERN CANADA TROF UNDER WEAKENING NEGATIVE
AO/NAO WHICH MEDIUM RANGE MODELS ARE HANDLING DIFFERENTLY.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND THE LOW
PRES SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
SUN NIGHT AND MON...00Z GFS NOW COMING ON BOARD WITH THE 00Z GEM-NH
AND 12Z/00Z ECMWF SHOWING INITIAL SHORTWAVE EJECTING ENE TOWARD THE
GREAT LAKES AHEAD OF DEVELOPING WRN CONUS TROF. WITH PRECIPITABLE
WATER VALUES RISING TO 160-180 PCT OF NORMAL AND STRENGTHENING 290K
ISENTROPIC ASCENT...AND 800-700 MB FGEN FORCING IN RIGHT ENTRANCE
REGION OF STRENGTHENING 100KT UPR JET MAX...WOULD EXPECT GOOD CHC OF
PCPN MOVING ACROSS THE FCST AREA. BASED ON 850MB TEMPS/1000-850MB
THICKNESS...WILL TREND PTYPE TO MOSTLY RAIN ACROSS ROUGHLY THE SE
HALF AND RAIN/SNOW MIX NW. INCLUDED FZRA SUN NIGHT INTO EARLY MON AS
WELL WHERE TEMPS WERE STILL SUBFREEZING. GIVEN HIGH PW
VALUES...THERE MAY BE A THREAT FOR MODERATE TO HEAVY RAIN AS THIS
SHORTWAVE MOVES THROUGH THE AREA. EXPECT PCPN TO TAPER OFF MON
EVENING AS FGEN FORCING WEAKENS.
WILL CONTINUE TO FAVOR A ECMWF/UKMET BLEND SOLN FOR TUE/WED FCST AS
THOSE MODELS APPEAR TO BETTER FIT THE PATTERN OF THE LINGERING BUT
WEAKENING NEGATIVE NAO WHICH HOLDS TROF IN OVER SE CANADA. IF THIS
SOLN WORKS OUT...DRY WEATHER SHOULD BE THE RULE TUE AND POSSIBLY
THRU WED AFTN BUT AGAIN CONFIDENCE WILL BE LOW UNTIL MODELS SORT OUT
TIMING/PLACEMENT OF SHORTWAVES LIFTING OUT OF THE WRN CONUS TROF. AS
MAIN PIECE OF ENERGY IN THE WRN TROF LIFTS NORTH TOWARD THE UPPER
GREAT LAKES...MODELS STILL POINT TOWARD EPISODE OF MDT TO POSSIBLY
HVY PCPN INTO UPPER MI AT SOME POINT WED-FRI. IF THE COLDER ECMWF IS
RIGHT...ANOTHER SIGNIFICANT SNOW COULD BE POSSIBLE FOR THE FCST
AREA...WHILE IF THE WARMER GFS AND 00Z GLOBAL GEM THERMAL FIELDS
VERIFY...MOSTLY RAIN WOULD BE EXPECTED SE HALF TO MOSTLY SNOW NW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 137 PM EDT SAT APR 6 2013
AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE LOW WILL MOVE INTO
THE AREA FROM SOUTHERN MN THIS AFTERNOON THROUGH TONIGHT. SLIGHTLY
WARMER TEMPERATURES ARE MOVING IN ALOFT ALLOWING THE SNOW TO MIX
AND IN SOME CASES CHANGE TO RAIN AS SUPPORTED BY RADAR AND SURFACE
OBSERVATIONS UP STREAM...WHICH WILL HELP TO INCREASE VISIBILITY
SLIGHTLY THIS AFTERNOON. EXPECT THIS TREND TO CONTINUE AT ALL TAF
SITES THIS AFTERNOON BEFORE SLOWLY TRANSITIONING TO SNOW FROM WEST
TO EAST OVERNIGHT. THIS TRANSITION TO ALL SNOW WILL REDUCE
VISIBILITY TO AROUND 1SM WITH CMX AND IWD POSSIBLY GOING TO 1/2SM
WITH THE HEAVIER SNOW BANDS THIS EVENING. AS THE TROUGH MOVES
OVERHEAD TONIGHT EXPECT CEILINGS TO DROP TO IFR OVER KSAW
OVERNIGHT...WHILE IWD AND CMX REMAIN AT IFR OR LOWER THROUGH THE
OVERNIGHT HOURS. AS THE LOW PRESSES EASTWARD LATE TONIGHT THROUGH
SUNDAY MORNING EXPECT VISIBILITY AND CEILINGS TO IMPROVE FIRST AT IWD
AND CMX AND LATER AT KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 610 AM EDT SAT APR 6 2013
A LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES REGION TODAY
AND TONIGHT WILL LEAD TO INCREASING SOUTHEASTERLY WINDS
TODAY...ESPECIALLY OVER EASTERN LAKE SUPERIOR WHERE GUSTS WILL
APPROACH 30KTS AND THERE COULD EVEN BE A FEW GALE FORCE GUSTS TO
35KTS. AS THE LOW SHIFTS EAST TONIGHT...WINDS WILL SHIFT TO THE
NORTHWEST UP TO 25KTS. HIGH PRESSURE WILL LEAD TO DIMINISHING WINDS
ON SUNDAY. NORTHERLY WINDS WILL INCREASE TO 20KTS ON MONDAY AS THE
PRESSURE GRADIENT INCREASES BETWEEN A HIGH IN CENTRAL CANADA AND A
LOW MOVING THROUGH THE LOWER GREAT LAKES. THE HIGH SHOULD LEAD TO
LIGHT NORTHEASTERLY WINDS ON TUESDAY...BUT ANOTHER LOW PRESSURE
SYSTEM POTENTIALLY MOVING THROUGH THE GREAT LAKES ON WEDNESDAY INTO
THURSDAY COULD LEAD TO STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-
013-014-085.
WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MIZ007.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ SUNDAY FOR
MIZ001>005-009-010-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KEC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1157 AM EDT SAT APR 6 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT SAT APR 6 2013
SHOWERS WILL INCREASE BY LATE AFTERNOON AS A LOW PRESSURE SYSTEM
APPROACHES THE AREA. THE STEADIEST RAINS ARE EXPECTED THIS EVENING
AS THE LOW AND A COLD FRONT TRACKS THROUGH THE GREAT LAKES. A
RUMBLE OF THUNDER IS ALSO POSSIBLE THIS EVENING. THE RAIN WILL END
OR BECOME WIDELY SCATTERED LATE TONIGHT. AFTER A QUIET
SUNDAY...MORE RAIN CAN BE EXPECTED LATE SUNDAY NIGHT INTO MONDAY.
DAYTIME HIGH TEMPERATURES WILL MAINLY BE IN THE 50S TODAY THROUGH
MONDAY...ALTHOUGH A FEW LOCALES COULD HIT THE 60 DEGREE MARK TODAY
AND AGAIN ON MONDAY.
MORE RAIN IS IN STORE FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
&&
.UPDATE...
ISSUED AT 1138 AM EDT SAT APR 6 2013
THE THREAT OF LIGHT SNOW OR MIXED RAIN AND SNOW NORTH OF I 96 IS
ENDING AS WARM FRONTAL PRECIP LIFTS OUT OF THE AREA AND SFC TEMPS
WARM THROUGH THE 40S. THE MAIN STORY NOW FOR THE REST OF THE DAY
IS BREEZY CONDITIONS WITH RISING TEMPS. WARMEST HIGH TEMPS... IN
THE LOWER 60S... SHOULD BE IN THE SW CORNER OF THE CWFA.
MEANWHILE THE NE CORNER NEAR CLARE MAY STRUGGLE TO HIT 50.
UPDATE ISSUED AT 726 AM EDT SAT APR 6 2013
BASED ON THE RADAR AND SURFACE OBSERVATIONS NOW SHOWING
PRECIPITATION REACHING THE GROUND FROM MKG TO LDM... RAIN AT MKG
AND LIGHT SNOW AT LDM... PLUS CONSIDERING THE LATEST RUNS OF THE
RAP ARW HRRR MODELS I INCREASED POPS OVER THE NORTHERN CWA INTO
MID MORNING. I ALSO USED THE HRRR TO UPDATE THE TEMP AND WIND
GRIDS... THIS GIVES WARMER AFTERNOON TEMPERATURES AND HIGHER WIND
GUSTS. GIVEN THE LATEST NAM12 1000 TO 925 MB THICKNESS VALUES THE
HRRR HIGHER MAX TEMPS (NEAR 60 SOUTH OF INTERSTATE 96) MAKE SENSE.
THAT WILL ENABLE DEEPER MIXING AND HIGHER WIND GUSTS TOO.
STILL LOOKS GOOD FOR SOME ISOLATED THUNDERSTORMS CROSSING LAKE
MICHIGAN INTO SOUTHWEST LOWER MICHIGAN (SPC 03Z SREF/NAM12 MAX
CAPE) IN THE 8 PM TO MIDNIGHT TIME FRAME. SEEMS IT WILL MOST BE
SOUTH OF MKG AND WEST OF US-131.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM EDT SAT APR 6 2013
HIGH PRESSURE WAS SLIPPING OFF TO THE EAST THIS MORNING. A WARM
FRONT WAS MOVING NORTHWARD ACROSS IL...ATTACHING TO LOW PRESSURE
OVER SE SD.
LOOKS LIKE WE WILL GET A SHORT BURST OF WARM ADVECTION PCPN THIS
MORNING. THIS WILL BE DRIVEN BY A LOW LEVEL JET WHICH WILL BE
INTERSECTING THE WARM FRONT. THE PCPN WILL BE MAINLY SNOW NE OF
GRR...ALTHOUGH ACCUMS SHOULD ONLY BE A LIGHT DUSTING BEFORE ANY PCPN
CHANGES TO ALL RAIN LATE THIS MORNING. ONCE THIS PCPN MOVES THROUGH
WE SHOULD SEE A LULL IN THE PCPN MID DAY...ALTHOUGH A FEW SHOWERS
MAY LINGER FAR NORTH. THEN AS THE SURFACE COLD FRONT AND LOW
APPROACHES THE RAIN SHOULD BECOME STEADIER AND MORE WIDESPREAD AFTER
21Z TODAY FROM NW TO SE. TEMPS ACROSS THE CWA...NE AREAS JUST
REACHING AROUND 50...WHILE SW AREAS SHOULD REACH AROUND 60 AS THIS
AREA WILL BE IN THE WARM SECTOR OF AWHILE TODAY.
THE BULK OF THE RAIN SHOULD COME THIS EVENING...AHEAD OF THE FROPA.
STILL ENOUGH INSTABILITY AND CAPE NEAR THE FRONT TO MAINTAIN THE
MENTION OF THUNDER FOR ALL OF THE CWA. STEADIEST RAINS SHOULD BE
OVER THE NORTHERN CWA...CLOSEST TO THE SURFACE LOW WHERE A QUARTER A
HALF INCH OF RAIN SHOULD OCCUR. MOST AREAS SOUTH AND EAST OF GRR
SHOULD SEE LESS THAN A QUARTER INCH.
THE FORECAST OF A DRY SUNDAY STILL LOOKS GOOD WITH WEAK SURFACE AND
UPPER RIDGING MOVING IN. HOW QUICKLY WE WILL CLEAR WILL MAKE FOR A
TOUGH TEMP FORECAST. ENOUGH SUN COULD PUSH TEMPS WELL INTO THE
50S...OR IF THE CLOUDS WERE TO LINGER WE MAY STRUGGLE TO REACH 50.
WILL GO OPTIMISTICALLY AS CLEARING LOOKS FAIRLY LIKELY BY AFTERNOON
AND WILL RAISE MAX TEMPS.
WILL ADD SOME TIMING IN THE GRIDS FOR SUNDAY NIGHT AS THE PCPN
SHOULD ARRIVE AFTER MIDNIGHT. THE MOISTURE DOES NOT RETURN UNTIL
THEN AND THE FORCING REMAINS WEAK THROUGH THE EVENING. HOWEVER
AFTER MIDNIGHT A WARM FRONT WILL SLOWLY LIFT NORTH ACROSS NRN
INDIANA AND SPREAD DEEPER MOISTURE INTO LOWER MI. UPPER DIVERGENCE
FROM THE RIGHT ENTRANCE REGION OF A JET WILL MOVE IN BETWEEN 06Z AND
12Z AND AREAS ALONG AND SOUTH OF I-96 SHOULD SEE RAIN DEVELOP.
FORCING CONTINUES INTO MONDAY AND SPREADS NORTH ACROSS ALL OF THE
CWA. THE WARM FRONT SHOULD MOVE NORTH INTO SOUTHERN SECTIONS OF THE
CWA. THIS WILL MAKE FOR ANOTHER TOUGH TEMP FORECAST. EXPECT AREAS
SOUTH OF THE FRONT WILL GET WELL INTO THE 60S...WHILE HOLDING IN THE
50S NORTH OF THE FRONT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT APR 6 2013
WE CONTINUE TO MONITOR THE POTENTIAL FOR A SIGNIFICANT RAIN...
FREEZING RAIN OR THUNDERSTORM EVENT IN THE WEDNESDAY TIME FRAME AS
THE ENERGY FROM THE SOUTHERN STREAM SYSTEM IS BOOTED OUT INTO THE
CENTRAL PLAINS AND GREAT LAKES. THE ISSUE IS IF THE ECMWF OR THE GFS
IS CORRECT ON THE TRACK OF THE SYSTEM.
AS HAS BEEN TRUE AND TO THIS POINT CONTINUES TO BE TRUE IS THE ECMWF
CONTINUES TO TRACK THE WED SYSTEM SOUTH OF LOWER MICHIGAN. THAT
KEEPS THE BEST INSTABILITY AND STRONGER THUNDERSTORMS SOUTH OF
MICHIGAN TOO. HOWEVER WE WOULD GET A DECENT OVERRUNNING RAIN EVENT IF
THE ECMWF TURNS OUT TO BE CORRECT. IT SHOULD BE NOTED THAT FOR 4
RUNS OF THE GFS IN A ROW THE WEDNESDAY SYSTEM IS FARTHER SOUTH ON
EACH RUN. FOR EXAMPLE... THE 05TH 06Z RUN OF THE GFS VALID AT 00Z ON
THE 11TH HAD THE SURFACE LOW OVER LAKE SUPERIOR.... BY THE 06TH AT
00Z THAT SAME SYSTEM IS NOW FORECAST OVER SOUTHERN LAKE MICHIGAN BY
THE GFS. THIS SUGGESTS TO ME THE ECMWF WILL TURN OUT TO BE CORRECT
WITH THE MORE SOUTHERLY TRACK OF THE SYSTEM. AS A RESULT OF THAT WE
CONTINUE TO FEATURE COLDER SURFACE TEMPERATURES TUESDAY THROUGH
THURSDAY.
ANOTHER ASPECT OF THE MORE SOUTHERLY TRACK OF THE ECMWF WEDNESDAY IS
THE COLD AIR BRINGING THE POTENTIAL FOR A FREEZING RAIN EVENT TO THE
CENTRAL AND NORTHERN CWA. THE ECMWF HAS SURFACE TEMPERATURES NEAR
FREEZING NEAR AND NORTH OF INTERSTATE 96 DURING THE DAY TIME HOURS
OF WEDNESDAY. GIVEN THE FEED OF CANADIAN POLAR AIR INTO THE AREA IF
THE ECMWF...WHEN YOU CONSIDER THE STEADY PRECIPITATION FALLING ALL
DAY WEDNESDAY THAT MAY WELL BE TRUE. IF THAT IS TRUE WE COULD SEE A
FREEZING RAIN EVENT WEDNESDAY. I DID NOT PLAY THIS SCENARIO IN THE
GRIDS BUT WE WILL HAVE TO WATCH THIS AS IT COULD BE THE MOST
SIGNIFICANT ASPECT OF THIS STORM FOR SOUTHWEST MICHIGAN.
THE ECMWF IS SLOWER TO MOVE THE SYSTEM OUT OF THE AREA... SO THE
PRECIPITATION WOULD CONTINUE INTO FRIDAY BUT FOR NOW I DID NOT SHOW
MUCH PRECIPITATION FRIDAY. WE CAN ADD THAT AS THE TIME GETS CLOSER.
OTHER THAN THAT ALL THE MODELS AGREE THE SYSTEM ON MONDAY WILL BE
DEPARTING THE AREA MONDAY EVENING BUT THE ECMWF CONTINUES TO SHOW
THE CANADIAN SURFACE HIGH BUILDING MORE STRONGLY SOUTH INTO THE
GREAT LAKES TUESDAY. THAT IN TURN PUSHES THE FRONT FARTHER SOUTH
THAN ON THE GEM OR GFS. THAT WOULD LIMIT THE NORTHWARD EXTENT OF
RAINFALL TUESDAY SO I TRIMMED THE POP LOWER OVER OUR NORTHERN CWA TO
ACCOUNT OF THAT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 726 AM EDT SAT APR 6 2013
I SEE VFR CONDITIONS PREVAILING THROUGH THIS EVENING UNTIL THE COLD
FRONT COMES THROUGH. THERE WILL BE A PLUME OF HIGHER DEW POINT AIR
JUST AHEAD OF THE SURFACE COLD FRONT WITH DEW POINTS IN THE MID
40S... SINCE THAT IS ABOUT WHAT THE AIR TEMPERATURE BEHIND THE
FRONT WILL BE LATER TONIGHT... THAT MIXING OF THE COLDER AIR WITH
THE MORE MOIST AIR WILL LIKELY RESULT IN A PERIOD OF LOW CLOUDS
BEHIND THE COLD FRONT... MOSTLY AFTER MIDNIGHT. I IMAGINE MVFR
CIGS FOR SURE AND COULD EVEN SEE SOME IFR FOR A FEW HOURS BEFORE
ENOUGH DRY AIR MOVES IN BEHIND THE FRONT TO MIX OUT THE LOW
CEILINGS. THIS IS SEEN NICELY IN BUFKIT TIME SECTIONS FROM THE
NAM12...THE GFS AND ARW MODELS AT ALL TAF SITES.
THE THREAT FOR THUNDERSTORMS THIS EVENING IS MOSTLY FOR THE
MKG...GRR AND AZO TAF SITES BUT IT IS MINIMAL (CAPE IS MINIMAL).
SO AT THIS POINT I WILL NOT FEATURE IT IN THE TAFS.
THE AREA OF PRECIPITATION SEEN ON RADAR LIFTING TO THE NE (GAVE MKG
SOME LIGHT RAIN FOR ABOUT A HALF HOUR AROUND 6 AM) SO THAT WILL
NOT BE A FACTOR ON THE TAFS TODAY.
&&
.MARINE...
ISSUED AT 1155 AM EDT SAT APR 6 2013
SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR THE ENTIRE NEARSHORE
AREA. WHILE THE SOUTH FLOW WILL RESULT IN LOWER WAVE HEIGHTS
SOUTH OF HOLLAND AS COMPARED TO AREAS NORTH OF HOLLAND... THE
MAGNITUDE OF THE WIND UP TO 30 KNOTS TODAY STILL MEETS SMALL CRAFT
ADVISORY CRITERIA.
WINDS AND WAVES SHOULD DIMINISH TOWARD MID DAY SUNDAY WITH RIDGING
MOVING IN.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT SAT APR 6 2013
TWO PERIODS OF RAIN IN THE SHORT TERM. IN BOTH CASES THE STEADIEST
RAINS ARE EXPECTED MAINLY NORTHWEST OF A MOP-BIV LINE. UP TO A HALF
INCH OF RAIN CAN BE EXPECTED NORTH OF THIS LINE THROUGH TONIGHT...
AND THEN AGAIN LATE SUNDAY NIGHT INTO MONDAY. AREAS SOUTHEAST OF
THE LINE SHOULD SEE LESS THAN A QUARTER INCH THROUGH TONIGHT...THEN
BETWEEN A QUARTER AND HALF INCH INTO MONDAY.
WE HAVE BEEN RATHER DRY OF LATE SO THE RIVER SHOULD BE ABLE HANDLE
THIS PCPN WITH ONLY MINOR RISES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON EDT SUNDAY FOR LMZ844>849.
&&
$$
UPDATE...MEADE
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1121 AM EDT SAT APR 6 2013
.UPDATE...
ISSUED AT 1118 AM EDT SAT APR 6 2013
SYSTEM WAS EXPECTED TO BE COMPLICATED...AND IT IS. 999MB SFC LOW
NEAR SIOUX FALLS SD AT 15Z. INITIAL BATCH OF WARM AIR ADVECTION SNOW
HAS BEEN LIGHTER THAN EXPECTED...AND NOW THE WARM AIR IS POISED TO
SWEEP NORTH AHEAD OF STRONGER/FARTHER NORTH 925-850MB LOWS OVER
MINNESOTA. MENTIONED MORE RAIN TODAY...ESPECIALLY IN THE WEST AS
950MB TEMPS CLIMB TOWARD +3C BY 18Z. ALREADY RECEIVING REPORTS JUST
WEST OF CWA OF ONLY RAIN. MAY NEED TO INCLUDE FZRA TOO AS SFC TEMPS
ARE STILL IN THE UPR 20S TO AROUND 30 DEGREES. JUST RECEIVED REPORT
OF SOME FREEZING RAIN MIXING WITH SNOW ON THE KEWEENAW. UPSTREAM
THERE IS NOT MUCH IN WAY OF PRECIPITATION FOR NEXT FEW HOURS.
YET...THERE IS INCREASING ECHOES/REPORTS OF PCPN OVER NORTHERN INTO
NORTHEAST MINNESOTA IN THE LAST TWO HOURS. THIS AREA OF PRECIPITATION
SHOULD SLIDE ACROSS WESTERN/NORTHWEST CWA THIS AFTN. ELSEWHERE...EXPECT
STEADY LIGHT SNOW TO SHIFT STEADILY EAST AND THEN TAPER OFF TO SCT
RAIN/SNOW SHOWERS THROUGH THE AFTN. ONLY RAIN EXPECTED OVER MUCH OF
SOUTHWEST AND SOUTH CNTRL AND...BASED ON 950MB TEMPS +1C TO +2C WITH
LACK OF LARGE SCALE LIFTING/DYNAMIC COOLING PROCESSES...MAYBE AS FAR
NORTH AS BARAGA/MARQUETTE/ALGER COUNTIES AS WELL AFTER MID AFTN.
STEADIER PRECIP THEN MAKES IT INTO CNTRL CWA TOWARD 21Z...WHICH MAY
RESULT IN MIX OF RAIN/SNOW...ESPECIALLY OVER HIGHER TERRAIN OF BARAGA
AND MARQUETTE COUNTIES.
COULD GET INTERESTING TONIGHT OVER THE WEST. H5 SHORTWAVE TROUGH TO
WEST THIS MORNING WAS SPLIT INTO TWO MAIN SECTIONS...ONE OVR
NORTHERN MINNESOTA TIED INTO MAIN H7 TROUGH...AND THE OTHER OVR
PUSHING ACROSS SOUTHEAST SD/SOUTHWEST MN. NORTHERN WAVE IS DRIVING
PRECIP OVER NORTHERN MN AND THEN AS SOUTHERN WAVE CATCHES UP TO THIS
WAVE THIS EVENING...THERE IS INDICATIONS DEFORMATION BAND OF PRECIP
WILL QUICKLY TAKE SHAPE OVER WESTERN UPR MICHIGAN. PTYPE A CONCERN
BUT ONLY INITIALLY AS STRENGTH OF DEFORMATION AND COOLING DUE TO
NORTHERN WAVE SHOULD CHANGE ANY RAIN OVER TO SNOW RATHER QUICKLY.
HRRR/RUC13/NAM ALL SHOW SIMILAR IDEA OF A 2-4 HR PERIOD OF HEAVIER
QPF. FOR THIS REASON...WILL KEEP GOING ADVY EVEN THOUGH MAIN PTYPE
TODAY WILL BE RAIN. OTHERWISE...EXTENT/TIMING OF REMAINDER
ADVISORIES LOOK GOOD BASED ON CURRENT RADAR TRENDS AND/OR EXPECTED
CHANGEOVER TO RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 610 AM EDT SAT APR 6 2013
VERY...VERY COMPLICATED FORECAST WITH ONGOING CHANGES IN THE MODEL
PRECIPITATION LOCATION/AMOUNTS/TYPES.
CURRENTLY...HIGH PRESSURE IS EXITING LOWER MICHIGAN WHILE A 998MB
LOW PRESSURE SYSTEM IS LOCATED IN SOUTHEAST SD. BETWEEN THESE TWO
FEATURES...BROAD LOW-MID LEVEL WARM AIR ADVECTION HAS LEAD TO LIGHT
TO OCCASIONALLY MODERATE SNOW SHOWERS OVER NORTHWEST WISCONSIN AND
MINNESOTA...WHICH HAS SHIFTED INTO SOUTHWESTERN UPPER MICHIGAN OVER
THE LAST COUPLE OF HOURS. DRY LOW LEVEL AIR SEEN ON 00Z KGRB/KINL
SOUNDINGS SEEMS TO HAVE BEEN LIMITING THE INTENSITY OF THE SNOW
THUS FAR...WITH MOST SITES REPORTING VISIBILITIES IN THE 1.5-3MI
RANGE.
THIS FIRST WAVE OF SNOW WILL CONTINUE TO THE EAST-NORTHEAST THROUGH
THE MORNING HOURS AND WITH THE UNDERWHELMING NATURE THUS FAR...IT
SEEMS THE LATEST MODEL TRENDS ARE ON TRACK. EVEN THOUGH THERE IS
PERSISTENT 925-700MB WAA/FGEN AREA THIS MORNING...THE DRY AIR
WILL KEEP SNOW AMOUNTS IN THE 1-3 INCH RANGE AT THE MOST AS THIS
AREA OF SNOW MOVES THROUGH...WITH MOST LOCATIONS SEEING AMOUNTS ON
THE LOW END OF THAT. THERE ARE A FEW CONVECTIVE LOOKING SNOW
SHOWERS FARTHER TO THE SOUTHWEST IN CENTRAL WI/MN THAT HAVE
DEVELOPED OVER THE LAST COUPLE HOURS. THESE MAY HELP FILL IN SOME
OF THE LIGHTER SNOW AREAS...BUT THE COVERAGE WILL LIKELY BE
LIMITED.
THE MORE QUESTIONABLE AND UNCERTAIN PORTION OF THE FORECAST COMES
THIS AFTERNOON INTO TONIGHT...ALTHOUGH LATEST RUNS SEEM TO HAVE THE
SAME IDEA ON A MORE NORTHERLY TRACK TO THE LOW. WV IMAGERY SHOWING
THE MAIN SHORTWAVE WITH THE LOW CURRENTLY ENTERING WESTERN SOUTH
DAKOTA WHILE THE LOW IS IN EASTERN SD. AS THESE TWO FEATURES COME
TOGETHER...EXPECT THE LOW TO INTENSIFY AND LIFT TO THE EAST
NORTHEAST INTO CENTRAL/NORTHERN WI LATE THIS AFTERNOON AND THEN
ACROSS THE MACKINAC STRAITS AROUND 06Z AND JUST NORTH OF THE
GEORGIAN BAY BY 12Z SUNDAY. ALL MODELS NOW HAVE THE IDEA OF WARMER
AIR PUSHING FARTHER NORTH INTO UPPER MICHIGAN THIS AFTERNOON AND
EVENING...AS THE NEXT SWATH OF PRECIPITATION DEVELOPS ON THE NORTH
AND NORTHWEST SIDE OF THE INTENSIFYING LOW. THE FIRST QUESTION MARK
IS IF THERE WILL BE ENOUGH MOISTURE TO LEAD TO PRECIPITATION
REDEVELOPING OVER THE CENTRAL CWA THIS AFTERNOON. WITH THE FIRST
AREA OF PRECIPITATION BECOMING ORIENTATED WEST-EAST ACROSS CENTRAL
LAKE SUPERIOR...THE PERSISTENT WAA FROM 925-700MB AND INCREASING
MOISTURE FROM THE APPROACHING LOW SHOULD LEAD TO SOME SHOWER
REDEVELOPMENT. THE QUESTION IS WHAT TYPE THE PRECIPITATION WILL BE.
WITH THE INCREASING WARM AIR AT THE LOW LEVELS...COULD SEE IT BEING
RAIN OR SNOW OVER THE NORTH HALF OF THE CWA AND RAIN FARTHER SOUTH.
THE LOCATIONS WITH THE MOST WORRIES FOR ACCUMULATIONS WILL BE FROM
THE HIGHER TERRAIN OF MARQUETTE/BARAGA COUNTIES WEST TO GOGEBIC. IN
THIS AREA...BOTH THE COMBINATION OF SURFACE TEMPS IN THE MID 30S
AND A NEARLY ISOTHERMAL TEMPERATURES FOR THE LAST 3-5KFT AROUND 1C
CAUSE CONCERN. JUST A SLIGHT VARIATION IN TEMPERATURES COULD PUSH
PRECIP TO ALL RAIN OR ALL SNOW. WITH THE WARMER TEMPS NEAR THE
SURFACE...HAVE TRENDED MORE TOWARDS A RAIN/SNOW MIX AND EVENTUALLY
TO MOSTLY RAIN AROUND 00Z WHEN THE PEAK WARM AIR IS OVER THE WEST.
SNOW ACCUMULATIONS THEN BECOME A CONCERN...AS THE TEMPS WOULD LIMIT
ACCUMULATION BUT HEAVIER BURSTS COULD PRODUCE A QUICK INCH. FARTHER
TO THE NORTH...EXPECT IT TO MAINLY BE SNOW OVER THE KEWEENAW
PENINSULA.
AS THE LOW TRANSITIONS ENE THROUGH WI AND TOWARDS THE STRAITS OF
MACKINAC TONIGHT...EXPECT A STRONGER AREA OF PRECIPITATION JUST
NORTH OF THE LOW LATE THIS AFTERNOON THROUGH THE EVENING HOURS.
WITH THE WARM AIR EXPECTED IN PLACE OVER THE CENTRAL AND
EAST...WOULD THINK MOST OF THE PRECIP WOULD BE RAIN UNTIL LATE IN
THE NIGHT. OVER THE WEST CENTRAL...SNOWFALL AMOUNTS LARGELY DEPEND
ON TRANSITION TIMING. AN HOUR OR TWO DIFFERENCE COULD MEAN A
SEVERAL INCH DIFFERENCE IN SNOWFALL...AND HAVE WENT ON THE
CONSERVATIVE SIDE WITH ANOTHER 1-3IN TONIGHT FROM THE HIGHER
TERRAIN OF MARQUETTE COUNTY AND WEST. 21Z/03Z SREF PROBABILITIES
AGREE WITH THIS ASSESSMENT OF A BETTER CHANCE OF RAIN BY 00Z AND
THEN CHANGING TO SNOW FROM WEST TO EAST...SO HAVE DEFINITELY
TRENDED THE FORECAST IN THAT DIRECTION. BEHIND THE LOW...900-875MB
TEMPS FALLING TO AROUND -7C LEADS TO ENOUGH LAKE INSTABILITY TO
PRODUCE LAKE ENHANCED SNOWFALL OVER THE NORTHWEST FAVORED LOCATIONS
OVER WESTERN UPPER MICHIGAN AFTER MIDNIGHT AND INTO THE OVERNIGHT
HOURS...BEFORE THE DEEPER MOISTURE QUICKLY DEPARTS FROM WEST TO EAST
AND QUICKLY LOWERS INVERSION HEIGHTS TO 3KFT BY 12Z ON SUNDAY.
ONE INTERESTING ITEM IS THE AMOUNT OF WARM AIR THAT THE LATEST RAP
RUNS PUSH INTO THE AREA. IT HAS KMNM REACHING THE LOWER 50S AND
KIMT/KESC IN THE MID 40S AND EVEN SOME OF KIWD TO KSAW NEARING 40
DEGREES. THIS MAY NOT BE TOO CRAZY...WITH LIMITED DEEP MOISTURE
FARTHER TO THE SOUTHWEST WITH MAINLY MID/HIGH CLOUDS OVER SOUTHERN
WI AND SOUTHERN MN. THIS WOULD LEAD TO A FILTERED SUNSHINE AND
ALLOW MORE HEATING TO REACH THE AREA. HAVE ADJUSTED TEMPS UP SOME
FOR TODAY TO ACCOUNT FOR THIS...BUT NOT AS HIGH AS THE RAP IS
INDICATING.
SO...WHAT TO DO WITH THE HEADLINES. WILL LEAVE THE ADVISORIES AS IS
FOR THE MORNING HOURS DUE TO THE SNOW MOVING INTO THE
AREA...ALTHOUGH THERE IS A GOOD CHANCE MANY LOCATIONS WON/T SEE
ADVISORY TOTALS. FOR AREAS OVER THE SOUTH CENTRAL AND EAST...MOVED
UP ENDING TIME TO MATCH WHEN INITIAL SNOW IS DONE AND EXPECTED
CHANGE OVER TO RAIN. OVER THE WEST...THERE WAS ENOUGH UNCERTAINTY
TO LEAVE THEM AS IS...ALTHOUGH DID EXTEND THE TIME TO BE A LITTLE
LATER. NRN HOUGHTON AND KEWEENAW IS ONE AREA WHERE THERE IS SOME
CONCERN FOR WARNING SNOW AMOUNTS DUE TO THEM STAYING MAINLY SNOW
AND THE INITIAL WAA PRECIPITATION PIVOTING THERE THIS
AFTERNOON/EVENING. ONLY ABOUT 5-6 21Z SREF MEMBERS THAT GET SNOWFALL
AMOUNTS OVER 6IN IN THAT AREA THROUGH TONIGHT. WITH DAYTIME
HEATING LIKELY LIMITING AMOUNT OF ACCUMULATION ON ROADWAYS AND
LIMITED CONFIDENCE ON 6IN...WILL LEAVE AT ADVISORY FOR NOW ALTHOUGH
DAY SHIFT WILL NEED TO MONITOR TRENDS AND POTENTIALLY UPGRADE TO
WARNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 610 AM EDT SAT APR 6 2013
MODELS STILL EXHIBIT GREAT VARIABILITY AND UNCERTAINTY FOR THE
EXTENDED PERIOD OF THE FCST. MUCH OF UNCERTAINTY HINGES ON THE
STRENGTH OF THE LINGERING ERN CANADA TROF UNDER WEAKENING NEGATIVE
AO/NAO WHICH MEDIUM RANGE MODELS ARE HANDLING DIFFERENTLY.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND THE LOW
PRES SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
SUN NIGHT AND MON...00Z GFS NOW COMING ON BOARD WITH THE 00Z GEM-NH
AND 12Z/00Z ECMWF SHOWING INITIAL SHORTWAVE EJECTING ENE TOWARD THE
GREAT LAKES AHEAD OF DEVELOPING WRN CONUS TROF. WITH PRECIPITABLE
WATER VALUES RISING TO 160-180 PCT OF NORMAL AND STRENGTHENING 290K
ISENTROPIC ASCENT...AND 800-700 MB FGEN FORCING IN RIGHT ENTRANCE
REGION OF STRENGTHENING 100KT UPR JET MAX...WOULD EXPECT GOOD CHC OF
PCPN MOVING ACROSS THE FCST AREA. BASED ON 850MB TEMPS/1000-850MB
THICKNESS...WILL TREND PTYPE TO MOSTLY RAIN ACROSS ROUGHLY THE SE
HALF AND RAIN/SNOW MIX NW. INCLUDED FZRA SUN NIGHT INTO EARLY MON AS
WELL WHERE TEMPS WERE STILL SUBFREEZING. GIVEN HIGH PW
VALUES...THERE MAY BE A THREAT FOR MODERATE TO HEAVY RAIN AS THIS
SHORTWAVE MOVES THROUGH THE AREA. EXPECT PCPN TO TAPER OFF MON
EVENING AS FGEN FORCING WEAKENS.
WILL CONTINUE TO FAVOR A ECMWF/UKMET BLEND SOLN FOR TUE/WED FCST AS
THOSE MODELS APPEAR TO BETTER FIT THE PATTERN OF THE LINGERING BUT
WEAKENING NEGATIVE NAO WHICH HOLDS TROF IN OVER SE CANADA. IF THIS
SOLN WORKS OUT...DRY WEATHER SHOULD BE THE RULE TUE AND POSSIBLY
THRU WED AFTN BUT AGAIN CONFIDENCE WILL BE LOW UNTIL MODELS SORT OUT
TIMING/PLACEMENT OF SHORTWAVES LIFTING OUT OF THE WRN CONUS TROF. AS
MAIN PIECE OF ENERGY IN THE WRN TROF LIFTS NORTH TOWARD THE UPPER
GREAT LAKES...MODELS STILL POINT TOWARD EPISODE OF MDT TO POSSIBLY
HVY PCPN INTO UPPER MI AT SOME POINT WED-FRI. IF THE COLDER ECMWF IS
RIGHT...ANOTHER SIGNIFICANT SNOW COULD BE POSSIBLE FOR THE FCST
AREA...WHILE IF THE WARMER GFS AND 00Z GLOBAL GEM THERMAL FIELDS
VERIFY...MOSTLY RAIN WOULD BE EXPECTED SE HALF TO MOSTLY SNOW NW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 753 AM EDT SAT APR 6 2013
AN APPROACHING LOW PRESSURE SYSTEM WILL BRING TWO BATCHES OF
PRECIPITATION TO THE AREA TODAY. THE FIRST HAS ALREADY MOVED THROUGH
KIWD AND IS MOVING THROUGH KCMX/KSAW AT THIS TIME. THIS SHOULD
REMAIN AS ALL SNOW AND WITH ADDITIONAL FORCING FARTHER TO THE
SOUTHWEST...CONTINUE FOR A COUPLE HOURS. ATTENTION THEN TURNS TO THE
NEXT WAVE ASSOCIATED WITH A LOW COMING OUT OF SOUTH DAKOTA WILL
APPROACH THE AREA LATER THIS AFTERNOON AND THROUGH TONIGHT. HAVE
CONTINUED THE TREND OF ANOTHER PERIOD OF LOWER
CEILINGS/VISIBILITIES...TO ALTERNATE LANDING MINS...FROM LATE
AFTERNOON AND EARLY EVENING WHEN THE BEST OPPORTUNITY OF PRECIP WILL
OCCUR. HELD VISIBILITIES UP INITIALLY AT KSAW...SINCE THEY WILL SEE
A RAIN/SNOW MIX. THE LOW WILL QUICKLY DEPART OVERNIGHT TONIGHT AND
BRING GRADUALLY IMPROVING CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 610 AM EDT SAT APR 6 2013
A LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES REGION TODAY
AND TONIGHT WILL LEAD TO INCREASING SOUTHEASTERLY WINDS
TODAY...ESPECIALLY OVER EASTERN LAKE SUPERIOR WHERE GUSTS WILL
APPROACH 30KTS AND THERE COULD EVEN BE A FEW GALE FORCE GUSTS TO
35KTS. AS THE LOW SHIFTS EAST TONIGHT...WINDS WILL SHIFT TO THE
NORTHWEST UP TO 25KTS. HIGH PRESSURE WILL LEAD TO DIMINISHING WINDS
ON SUNDAY. NORTHERLY WINDS WILL INCREASE TO 20KTS ON MONDAY AS THE
PRESSURE GRADIENT INCREASES BETWEEN A HIGH IN CENTRAL CANADA AND A
LOW MOVING THROUGH THE LOWER GREAT LAKES. THE HIGH SHOULD LEAD TO
LIGHT NORTHEASTERLY WINDS ON TUESDAY...BUT ANOTHER LOW PRESSURE
SYSTEM POTENTIALLY MOVING THROUGH THE GREAT LAKES ON WEDNESDAY INTO
THURSDAY COULD LEAD TO STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-
013-014-085.
WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MIZ007.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ SUNDAY FOR
MIZ001>005-009-010-084.
WINTER WEATHER ADVISORY UNTIL 11 AM CDT THIS MORNING FOR MIZ011-
012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
757 AM EDT SAT APR 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 610 AM EDT SAT APR 6 2013
VERY...VERY COMPLICATED FORECAST WITH ONGOING CHANGES IN THE MODEL
PRECIPITATION LOCATION/AMOUNTS/TYPES.
CURRENTLY...HIGH PRESSURE IS EXITING LOWER MICHIGAN WHILE A 998MB
LOW PRESSURE SYSTEM IS LOCATED IN SOUTHEAST SD. BETWEEN THESE TWO
FEATURES...BROAD LOW-MID LEVEL WARM AIR ADVECTION HAS LEAD TO LIGHT
TO OCCASIONALLY MODERATE SNOW SHOWERS OVER NORTHWEST WISCONSIN AND
MINNESOTA...WHICH HAS SHIFTED INTO SOUTHWESTERN UPPER MICHIGAN OVER
THE LAST COUPLE OF HOURS. DRY LOW LEVEL AIR SEEN ON 00Z KGRB/KINL
SOUNDINGS SEEMS TO HAVE BEEN LIMITING THE INTENSITY OF THE SNOW
THUS FAR...WITH MOST SITES REPORTING VISIBILITIES IN THE 1.5-3MI
RANGE.
THIS FIRST WAVE OF SNOW WILL CONTINUE TO THE EAST-NORTHEAST THROUGH
THE MORNING HOURS AND WITH THE UNDERWHELMING NATURE THUS FAR...IT
SEEMS THE LATEST MODEL TRENDS ARE ON TRACK. EVEN THOUGH THERE IS
PERSISTENT 925-700MB WAA/FGEN AREA THIS MORNING...THE DRY AIR
WILL KEEP SNOW AMOUNTS IN THE 1-3 INCH RANGE AT THE MOST AS THIS
AREA OF SNOW MOVES THROUGH...WITH MOST LOCATIONS SEEING AMOUNTS ON
THE LOW END OF THAT. THERE ARE A FEW CONVECTIVE LOOKING SNOW
SHOWERS FARTHER TO THE SOUTHWEST IN CENTRAL WI/MN THAT HAVE
DEVELOPED OVER THE LAST COUPLE HOURS. THESE MAY HELP FILL IN SOME
OF THE LIGHTER SNOW AREAS...BUT THE COVERAGE WILL LIKELY BE
LIMITED.
THE MORE QUESTIONABLE AND UNCERTAIN PORTION OF THE FORECAST COMES
THIS AFTERNOON INTO TONIGHT...ALTHOUGH LATEST RUNS SEEM TO HAVE THE
SAME IDEA ON A MORE NORTHERLY TRACK TO THE LOW. WV IMAGERY SHOWING
THE MAIN SHORTWAVE WITH THE LOW CURRENTLY ENTERING WESTERN SOUTH
DAKOTA WHILE THE LOW IS IN EASTERN SD. AS THESE TWO FEATURES COME
TOGETHER...EXPECT THE LOW TO INTENSIFY AND LIFT TO THE EAST
NORTHEAST INTO CENTRAL/NORTHERN WI LATE THIS AFTERNOON AND THEN
ACROSS THE MACKINAC STRAITS AROUND 06Z AND JUST NORTH OF THE
GEORGIAN BAY BY 12Z SUNDAY. ALL MODELS NOW HAVE THE IDEA OF WARMER
AIR PUSHING FARTHER NORTH INTO UPPER MICHIGAN THIS AFTERNOON AND
EVENING...AS THE NEXT SWATH OF PRECIPITATION DEVELOPS ON THE NORTH
AND NORTHWEST SIDE OF THE INTENSIFYING LOW. THE FIRST QUESTION MARK
IS IF THERE WILL BE ENOUGH MOISTURE TO LEAD TO PRECIPITATION
REDEVELOPING OVER THE CENTRAL CWA THIS AFTERNOON. WITH THE FIRST
AREA OF PRECIPITATION BECOMING ORIENTATED WEST-EAST ACROSS CENTRAL
LAKE SUPERIOR...THE PERSISTENT WAA FROM 925-700MB AND INCREASING
MOISTURE FROM THE APPROACHING LOW SHOULD LEAD TO SOME SHOWER
REDEVELOPMENT. THE QUESTION IS WHAT TYPE THE PRECIPITATION WILL BE.
WITH THE INCREASING WARM AIR AT THE LOW LEVELS...COULD SEE IT BEING
RAIN OR SNOW OVER THE NORTH HALF OF THE CWA AND RAIN FARTHER SOUTH.
THE LOCATIONS WITH THE MOST WORRIES FOR ACCUMULATIONS WILL BE FROM
THE HIGHER TERRAIN OF MARQUETTE/BARAGA COUNTIES WEST TO GOGEBIC. IN
THIS AREA...BOTH THE COMBINATION OF SURFACE TEMPS IN THE MID 30S
AND A NEARLY ISOTHERMAL TEMPERATURES FOR THE LAST 3-5KFT AROUND 1C
CAUSE CONCERN. JUST A SLIGHT VARIATION IN TEMPERATURES COULD PUSH
PRECIP TO ALL RAIN OR ALL SNOW. WITH THE WARMER TEMPS NEAR THE
SURFACE...HAVE TRENDED MORE TOWARDS A RAIN/SNOW MIX AND EVENTUALLY
TO MOSTLY RAIN AROUND 00Z WHEN THE PEAK WARM AIR IS OVER THE WEST.
SNOW ACCUMULATIONS THEN BECOME A CONCERN...AS THE TEMPS WOULD LIMIT
ACCUMULATION BUT HEAVIER BURSTS COULD PRODUCE A QUICK INCH. FARTHER
TO THE NORTH...EXPECT IT TO MAINLY BE SNOW OVER THE KEWEENAW
PENINSULA.
AS THE LOW TRANSITIONS ENE THROUGH WI AND TOWARDS THE STRAITS OF
MACKINAC TONIGHT...EXPECT A STRONGER AREA OF PRECIPITATION JUST
NORTH OF THE LOW LATE THIS AFTERNOON THROUGH THE EVENING HOURS.
WITH THE WARM AIR EXPECTED IN PLACE OVER THE CENTRAL AND
EAST...WOULD THINK MOST OF THE PRECIP WOULD BE RAIN UNTIL LATE IN
THE NIGHT. OVER THE WEST CENTRAL...SNOWFALL AMOUNTS LARGELY DEPEND
ON TRANSITION TIMING. AN HOUR OR TWO DIFFERENCE COULD MEAN A
SEVERAL INCH DIFFERENCE IN SNOWFALL...AND HAVE WENT ON THE
CONSERVATIVE SIDE WITH ANOTHER 1-3IN TONIGHT FROM THE HIGHER
TERRAIN OF MARQUETTE COUNTY AND WEST. 21Z/03Z SREF PROBABILITIES
AGREE WITH THIS ASSESSMENT OF A BETTER CHANCE OF RAIN BY 00Z AND
THEN CHANGING TO SNOW FROM WEST TO EAST...SO HAVE DEFINITELY
TRENDED THE FORECAST IN THAT DIRECTION. BEHIND THE LOW...900-875MB
TEMPS FALLING TO AROUND -7C LEADS TO ENOUGH LAKE INSTABILITY TO
PRODUCE LAKE ENHANCED SNOWFALL OVER THE NORTHWEST FAVORED LOCATIONS
OVER WESTERN UPPER MICHIGAN AFTER MIDNIGHT AND INTO THE OVERNIGHT
HOURS...BEFORE THE DEEPER MOISTURE QUICKLY DEPARTS FROM WEST TO EAST
AND QUICKLY LOWERS INVERSION HEIGHTS TO 3KFT BY 12Z ON SUNDAY.
ONE INTERESTING ITEM IS THE AMOUNT OF WARM AIR THAT THE LATEST RAP
RUNS PUSH INTO THE AREA. IT HAS KMNM REACHING THE LOWER 50S AND
KIMT/KESC IN THE MID 40S AND EVEN SOME OF KIWD TO KSAW NEARING 40
DEGREES. THIS MAY NOT BE TOO CRAZY...WITH LIMITED DEEP MOISTURE
FARTHER TO THE SOUTHWEST WITH MAINLY MID/HIGH CLOUDS OVER SOUTHERN
WI AND SOUTHERN MN. THIS WOULD LEAD TO A FILTERED SUNSHINE AND
ALLOW MORE HEATING TO REACH THE AREA. HAVE ADJUSTED TEMPS UP SOME
FOR TODAY TO ACCOUNT FOR THIS...BUT NOT AS HIGH AS THE RAP IS
INDICATING.
SO...WHAT TO DO WITH THE HEADLINES. WILL LEAVE THE ADVISORIES AS IS
FOR THE MORNING HOURS DUE TO THE SNOW MOVING INTO THE
AREA...ALTHOUGH THERE IS A GOOD CHANCE MANY LOCATIONS WON/T SEE
ADVISORY TOTALS. FOR AREAS OVER THE SOUTH CENTRAL AND EAST...MOVED
UP ENDING TIME TO MATCH WHEN INITIAL SNOW IS DONE AND EXPECTED
CHANGE OVER TO RAIN. OVER THE WEST...THERE WAS ENOUGH UNCERTAINTY
TO LEAVE THEM AS IS...ALTHOUGH DID EXTEND THE TIME TO BE A LITTLE
LATER. NRN HOUGHTON AND KEWEENAW IS ONE AREA WHERE THERE IS SOME
CONCERN FOR WARNING SNOW AMOUNTS DUE TO THEM STAYING MAINLY SNOW
AND THE INITIAL WAA PRECIPITATION PIVOTING THERE THIS
AFTERNOON/EVENING. ONLY ABOUT 5-6 21Z SREF MEMBERS THAT GET SNOWFALL
AMOUNTS OVER 6IN IN THAT AREA THROUGH TONIGHT. WITH DAYTIME
HEATING LIKELY LIMITING AMOUNT OF ACCUMULATION ON ROADWAYS AND
LIMITED CONFIDENCE ON 6IN...WILL LEAVE AT ADVISORY FOR NOW ALTHOUGH
DAY SHIFT WILL NEED TO MONITOR TRENDS AND POTENTIALLY UPGRADE TO
WARNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 610 AM EDT SAT APR 6 2013
MODELS STILL EXHIBIT GREAT VARIABILITY AND UNCERTAINTY FOR THE
EXTENDED PERIOD OF THE FCST. MUCH OF UNCERTAINTY HINGES ON THE
STRENGTH OF THE LINGERING ERN CANADA TROF UNDER WEAKENING NEGATIVE
AO/NAO WHICH MEDIUM RANGE MODELS ARE HANDLING DIFFERENTLY.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND THE LOW
PRES SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
SUN NIGHT AND MON...00Z GFS NOW COMING ON BOARD WITH THE 00Z GEM-NH
AND 12Z/00Z ECMWF SHOWING INITIAL SHORTWAVE EJECTING ENE TOWARD THE
GREAT LAKES AHEAD OF DEVELOPING WRN CONUS TROF. WITH PRECIPITABLE
WATER VALUES RISING TO 160-180 PCT OF NORMAL AND STRENGTHENING 290K
ISENTROPIC ASCENT...AND 800-700 MB FGEN FORCING IN RIGHT ENTRANCE
REGION OF STRENGTHENING 100KT UPR JET MAX...WOULD EXPECT GOOD CHC OF
PCPN MOVING ACROSS THE FCST AREA. BASED ON 850MB TEMPS/1000-850MB
THICKNESS...WILL TREND PTYPE TO MOSTLY RAIN ACROSS ROUGHLY THE SE
HALF AND RAIN/SNOW MIX NW. INCLUDED FZRA SUN NIGHT INTO EARLY MON AS
WELL WHERE TEMPS WERE STILL SUBFREEZING. GIVEN HIGH PW
VALUES...THERE MAY BE A THREAT FOR MODERATE TO HEAVY RAIN AS THIS
SHORTWAVE MOVES THROUGH THE AREA. EXPECT PCPN TO TAPER OFF MON
EVENING AS FGEN FORCING WEAKENS.
WILL CONTINUE TO FAVOR A ECMWF/UKMET BLEND SOLN FOR TUE/WED FCST AS
THOSE MODELS APPEAR TO BETTER FIT THE PATTERN OF THE LINGERING BUT
WEAKENING NEGATIVE NAO WHICH HOLDS TROF IN OVER SE CANADA. IF THIS
SOLN WORKS OUT...DRY WEATHER SHOULD BE THE RULE TUE AND POSSIBLY
THRU WED AFTN BUT AGAIN CONFIDENCE WILL BE LOW UNTIL MODELS SORT OUT
TIMING/PLACEMENT OF SHORTWAVES LIFTING OUT OF THE WRN CONUS TROF. AS
MAIN PIECE OF ENERGY IN THE WRN TROF LIFTS NORTH TOWARD THE UPPER
GREAT LAKES...MODELS STILL POINT TOWARD EPISODE OF MDT TO POSSIBLY
HVY PCPN INTO UPPER MI AT SOME POINT WED-FRI. IF THE COLDER ECMWF IS
RIGHT...ANOTHER SIGNIFICANT SNOW COULD BE POSSIBLE FOR THE FCST
AREA...WHILE IF THE WARMER GFS AND 00Z GLOBAL GEM THERMAL FIELDS
VERIFY...MOSTLY RAIN WOULD BE EXPECTED SE HALF TO MOSTLY SNOW NW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 753 AM EDT SAT APR 6 2013
AN APPROACHING LOW PRESSURE SYSTEM WILL BRING TWO BATCHES OF
PRECIPITATION TO THE AREA TODAY. THE FIRST HAS ALREADY MOVED THROUGH
KIWD AND IS MOVING THROUGH KCMX/KSAW AT THIS TIME. THIS SHOULD
REMAIN AS ALL SNOW AND WITH ADDITIONAL FORCING FARTHER TO THE
SOUTHWEST...CONTINUE FOR A COUPLE HOURS. ATTENTION THEN TURNS TO THE
NEXT WAVE ASSOCIATED WITH A LOW COMING OUT OF SOUTH DAKOTA WILL
APPROACH THE AREA LATER THIS AFTERNOON AND THROUGH TONIGHT. HAVE
CONTINUED THE TREND OF ANOTHER PERIOD OF LOWER
CEILINGS/VISIBILITIES...TO ALTERNATE LANDING MINS...FROM LATE
AFTERNOON AND EARLY EVENING WHEN THE BEST OPPORTUNITY OF PRECIP WILL
OCCUR. HELD VISIBILITIES UP INITIALLY AT KSAW...SINCE THEY WILL SEE
A RAIN/SNOW MIX. THE LOW WILL QUICKLY DEPART OVERNIGHT TONIGHT AND
BRING GRADUALLY IMPROVING CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 610 AM EDT SAT APR 6 2013
A LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES REGION TODAY
AND TONIGHT WILL LEAD TO INCREASING SOUTHEASTERLY WINDS
TODAY...ESPECIALLY OVER EASTERN LAKE SUPERIOR WHERE GUSTS WILL
APPROACH 30KTS AND THERE COULD EVEN BE A FEW GALE FORCE GUSTS TO
35KTS. AS THE LOW SHIFTS EAST TONIGHT...WINDS WILL SHIFT TO THE
NORTHWEST UP TO 25KTS. HIGH PRESSURE WILL LEAD TO DIMINISHING WINDS
ON SUNDAY. NORTHERLY WINDS WILL INCREASE TO 20KTS ON MONDAY AS THE
PRESSURE GRADIENT INCREASES BETWEEN A HIGH IN CENTRAL CANADA AND A
LOW MOVING THROUGH THE LOWER GREAT LAKES. THE HIGH SHOULD LEAD TO
LIGHT NORTHEASTERLY WINDS ON TUESDAY...BUT ANOTHER LOW PRESSURE
SYSTEM POTENTIALLY MOVING THROUGH THE GREAT LAKES ON WEDNESDAY INTO
THURSDAY COULD LEAD TO STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-
013-014-085.
WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MIZ007.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ SUNDAY FOR
MIZ001>005-009-010-084.
WINTER WEATHER ADVISORY UNTIL 11 AM CDT THIS MORNING FOR MIZ011-
012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
727 AM EDT SAT APR 6 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT SAT APR 6 2013
SCATTERED SHOWERS WILL OCCASIONALLY MIX WITH SNOW THIS MORNING...
BEFORE CHANGING TO ALL RAIN BY MID DAY. THE SHOWERS WILL
BECOME MORE COMMON BY LATE AFTERNOON AS A LOW PRESSURE SYSTEM
APPROACHES THE AREA. THE STEADIEST RAINS ARE EXPECTED THIS EVENING
AS THE LOW AND A COLD FRONT TRACKS THROUGH THE GREAT LAKES. A
RUMBLE OF THUNDER IS ALSO POSSIBLE THIS EVENING. THE RAIN WILL END
OR BECOME WIDELY SCATTERED LATE TONIGHT. AFTER A QUIET
SUNDAY...MORE RAIN CAN BE EXPECTED LATE SUNDAY NIGHT INTO MONDAY.
DAYTIME HIGH TEMPERATURES WILL MAINLY BE IN THE 50S TODAY THROUGH
MONDAY...ALTHOUGH A FEW LOCALES COULD HIT THE 60 DEGREE MARK TODAY
AND AGAIN ON MONDAY.
MORE RAIN IS IN STORE FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
&&
.UPDATE...
ISSUED AT 726 AM EDT SAT APR 6 2013
BASED ON THE RADAR AND SURFACE OBSERVATIONS NOW SHOWING
PRECIPITATION REACHING THE GROUND FROM MKG TO LDM... RAIN AT MKG
AND LIGHT SNOW AT LDM... PLUS CONSIDERING THE LATEST RUNS OF THE
RAP ARW HRRR MODELS I INCREASED POPS OVER THE NORTHERN CWA INTO
MID MORNING. I ALSO USED THE HRRR TO UPDATE THE TEMP AND WIND
GRIDS... THIS GIVES WARMER AFTERNOON TEMPERATURES AND HIGHER WIND
GUSTS. GIVEN THE LATEST NAM12 1000 TO 925 MB THICKNESS VALUES THE
HRRR HIGHER MAX TEMPS (NEAR 60 SOUTH OF INTERSTATE 96) MAKE SENSE.
THAT WILL ENABLE DEEPER MIXING AND HIGHER WIND GUSTS TOO.
STILL LOOKS GOOD FOR SOME ISOLATED THUNDERSTORMS CROSSING LAKE
MICHIGAN INTO SOUTHWEST LOWER MICHIGAN (SPC 03Z SREF/NAM12 MAX
CAPE) IN THE 8 PM TO MIDNIGHT TIME FRAME. SEEMS IT WILL MOST BE
SOUTH OF MKG AND WEST OF US-131.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM EDT SAT APR 6 2013
HIGH PRESSURE WAS SLIPPING OFF TO THE EAST THIS MORNING. A WARM
FRONT WAS MOVING NORTHWARD ACROSS IL...ATTACHING TO LOW PRESSURE
OVER SE SD.
LOOKS LIKE WE WILL GET A SHORT BURST OF WARM ADVECTION PCPN THIS
MORNING. THIS WILL BE DRIVEN BY A LOW LEVEL JET WHICH WILL BE
INTERSECTING THE WARM FRONT. THE PCPN WILL BE MAINLY SNOW NE OF
GRR...ALTHOUGH ACCUMS SHOULD ONLY BE A LIGHT DUSTING BEFORE ANY PCPN
CHANGES TO ALL RAIN LATE THIS MORNING. ONCE THIS PCPN MOVES THROUGH
WE SHOULD SEE A LULL IN THE PCPN MID DAY...ALTHOUGH A FEW SHOWERS
MAY LINGER FAR NORTH. THEN AS THE SURFACE COLD FRONT AND LOW
APPROACHES THE RAIN SHOULD BECOME STEADIER AND MORE WIDESPREAD AFTER
21Z TODAY FROM NW TO SE. TEMPS ACROSS THE CWA...NE AREAS JUST
REACHING AROUND 50...WHILE SW AREAS SHOULD REACH AROUND 60 AS THIS
AREA WILL BE IN THE WARM SECTOR OF AWHILE TODAY.
THE BULK OF THE RAIN SHOULD COME THIS EVENING...AHEAD OF THE FROPA.
STILL ENOUGH INSTABILITY AND CAPE NEAR THE FRONT TO MAINTAIN THE
MENTION OF THUNDER FOR ALL OF THE CWA. STEADIEST RAINS SHOULD BE
OVER THE NORTHERN CWA...CLOSEST TO THE SURFACE LOW WHERE A QUARTER A
HALF INCH OF RAIN SHOULD OCCUR. MOST AREAS SOUTH AND EAST OF GRR
SHOULD SEE LESS THAN A QUARTER INCH.
THE FORECAST OF A DRY SUNDAY STILL LOOKS GOOD WITH WEAK SURFACE AND
UPPER RIDGING MOVING IN. HOW QUICKLY WE WILL CLEAR WILL MAKE FOR A
TOUGH TEMP FORECAST. ENOUGH SUN COULD PUSH TEMPS WELL INTO THE
50S...OR IF THE CLOUDS WERE TO LINGER WE MAY STRUGGLE TO REACH 50.
WILL GO OPTIMISTICALLY AS CLEARING LOOKS FAIRLY LIKELY BY AFTERNOON
AND WILL RAISE MAX TEMPS.
WILL ADD SOME TIMING IN THE GRIDS FOR SUNDAY NIGHT AS THE PCPN
SHOULD ARRIVE AFTER MIDNIGHT. THE MOISTURE DOES NOT RETURN UNTIL
THEN AND THE FORCING REMAINS WEAK THROUGH THE EVENING. HOWEVER
AFTER MIDNIGHT A WARM FRONT WILL SLOWLY LIFT NORTH ACROSS NRN
INDIANA AND SPREAD DEEPER MOISTURE INTO LOWER MI. UPPER DIVERGENCE
FROM THE RIGHT ENTRANCE REGION OF A JET WILL MOVE IN BETWEEN 06Z AND
12Z AND AREAS ALONG AND SOUTH OF I-96 SHOULD SEE RAIN DEVELOP.
FORCING CONTINUES INTO MONDAY AND SPREADS NORTH ACROSS ALL OF THE
CWA. THE WARM FRONT SHOULD MOVE NORTH INTO SOUTHERN SECTIONS OF THE
CWA. THIS WILL MAKE FOR ANOTHER TOUGH TEMP FORECAST. EXPECT AREAS
SOUTH OF THE FRONT WILL GET WELL INTO THE 60S...WHILE HOLDING IN THE
50S NORTH OF THE FRONT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT APR 6 2013
WE CONTINUE TO MONITOR THE POTENTIAL FOR A SIGNIFICANT RAIN...
FREEZING RAIN OR THUNDERSTORM EVENT IN THE WEDNESDAY TIME FRAME AS
THE ENERGY FROM THE SOUTHERN STREAM SYSTEM IS BOOTED OUT INTO THE
CENTRAL PLAINS AND GREAT LAKES. THE ISSUE IS IF THE ECMWF OR THE GFS
IS CORRECT ON THE TRACK OF THE SYSTEM.
AS HAS BEEN TRUE AND TO THIS POINT CONTINUES TO BE TRUE IS THE ECMWF
CONTINUES TO TRACK THE WED SYSTEM SOUTH OF LOWER MICHIGAN. THAT
KEEPS THE BEST INSTABILITY AND STRONGER THUNDERSTORMS SOUTH OF
MICHIGAN TOO. HOWEVER WE WOULD GET A DECENT OVERRUNING RAIN EVENT IF
THE ECMWF TURNS OUT TO BE CORRECT. IT SHOULD BE NOTED THAT FOR 4
RUNS OF THE GFS IN A ROW THE WEDNESDAY SYSTEM IS FARTHER SOUTH ON
EACH RUN. FOR EXAMPLE... THE 05TH 06Z RUN OF THE GFS VALID AT 00Z ON
THE 11TH HAD THE SURFACE LOW OVER LAKE SUPERIOR.... BY THE 06TH AT
00Z THAT SAME SYSTEM IS NOW FORECAST OVER SOUTHERN LAKE MICHIGAN BY
THE GFS. THIS SUGGESTS TO ME THE ECMWF WILL TURN OUT TO BE CORRECT
WITH THE MORE SOUTHERLY TRACK OF THE SYSTEM. AS A RESULT OF THAT WE
CONTINUE TO FEATURE COLDER SURFACE TEMPERATURES TUESDAY THROUGH
THURSDAY.
ANOTHER ASPECT OF THE MORE SOUTHERLY TRACK OF THE ECMWF WEDNESDAY IS
THE COLD AIR BRINGING THE POTENTIAL FOR A FREEZING RAIN EVENT TO THE
CENTRAL AND NORTHERN CWA. THE ECMWF HAS SURFACE TEMPERATURES NEAR
FREEZING NEAR AND NORTH OF INTERSTATE 96 DURING THE DAY TIME HOURS
OF WEDNESDAY. GIVEN THE FEED OF CANADIAN POLAR AIR INTO THE AREA IF
THE ECMWF...WHEN YOU CONSIDER THE STEADY PRECIPITATION FALLING ALL
DAY WEDNESDAY THAT MAY WELL BE TRUE. IF THAT IS TRUE WE COULD SEE A
FREEZING RAIN EVENT WEDNESDAY. I DID NOT PLAY THIS SCENARIO IN THE
GRIDS BUT WE WILL HAVE TO WATCH THIS AS IT COULD BE THE MOST
SIGNIFICANT ASPECT OF THIS STORM FOR SOUTHWEST MICHIGAN.
THE ECMWF IS SLOWER TO MOVE THE SYSTEM OUT OF THE AREA... SO THE
PRECIPITATION WOULD CONTINUE INTO FRIDAY BUT FOR NOW I DID NOT SHOW
MUCH PRECIPITATION FRIDAY. WE CAN ADD THAT AS THE TIME GETS CLOSER.
OTHER THAN THAT ALL THE MODELS AGREE THE SYSTEM ON MONDAY WILL BE
DEPARTING THE AREA MONDAY EVENING BUT THE ECMWF CONTINUES TO SHOW
THE CANADIAN SURFACE HIGH BUILDING MORE STRONGLY SOUTH INTO THE
GREAT LAKES TUESDAY. THAT IN TURN PUSHES THE FRONT FARTHER SOUTH
THAN ON THE GEM OR GFS. THAT WOULD LIMIT THE NORTHWARD EXTENT OF
RAINFALL TUESDAY SO I TRIMMED THE POP LOWER OVER OUR NORTHERN CWA TO
ACCOUNT OF THAT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 726 AM EDT SAT APR 6 2013
I SEE VFR CONDITIONS PREVAILING THROUGH THIS EVENING UNTIL THE COLD
FRONT COMES THROUGH. THERE WILL BE PLUM OF HIGHER DEW POINT AIR
JUST AHEAD OF THE SURFACE COLD FRONT WITH DEW POINTS IN THE MID
40S... SINCE THAT IS ABOUT WHAT THE AIR TEMPERATURE BEHIND THE
FRONT WILL BE LATER TONIGHT... THAT MIXING OF THE COLDER AIR WITH
THE MORE MOIST AIR WILL LIKELY RESULT IN A PERIOD OF LOW CLOUDS
BEHIND THE COLD FRONT... MOSTLY AFTER MIDNIGHT. I IMAGINE MVFR
CIGS FOR SURE AND COULD EVEN SEE SOME IFR FOR A FEW HOURS BEFORE
ENOUGH DRY AIR MOVES IN BEHIND THE FRONT TO MIX OUT THE LOW
CEILINGS. THIS IS SEEN NICELY IN BUFKIT TIME SECTIONS FROM THE
NAM12...THE GFS AND ARW MODELS AT ALL TAF SITES.
THE THREAT FOR THUNDERSTORMS THIS EVENING IS MOSTLY FOR THE
MKG...GRR AND AZO TAF SITES BUT IT IS MINIMAL (CAPE IS MINIMAL).
SO AT THIS POINT I WILL NOT FEATURE IT IN THE TAFS.
THE AREA OF PRECIPITATION SEEN ON RADAR LIFTING TO THE NE (GAVE MKG
SOME LIGHT RAIN FOR ABOUT A HALF HOUR AROUND 6 AM) SO THAT WILL
NOT BE A FACTOR ON THE TAFS TODAY.
&&
.MARINE...
ISSUED AT 330 AM EDT SAT APR 6 2013
WILL MAINTAIN THE SCA FOR AREAS NORTH OF HOLLAND. HOWEVER WILL
ADJUST THE TIMING OF THE HEADLINE SOUTH OF HOLLAND TO JUST TONIGHT.
SOUTHEAST WINDS TODAY WILL CAUSE THE HIGHEST WAVES TO BE HOLLAND
NORTHWARD...THEN AS WINDS VEER TO THE SW AND W LATER TONIGHT...THE
ROUGHER CONDITIONS WILL ALSO MOVE INTO AREAS SOUTH OF HOLLAND.
WINDS AND WAVES SHOULD DIMINISH TOWARD MID DAY SUNDAY WITH RIDGING
MOVING IN.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT SAT APR 6 2013
TWO PERIODS OF RAIN IN THE SHORT TERM. IN BOTH CASES THE STEADIEST
RAINS ARE EXPECTED MAINLY NORTHWEST OF A MOP-BIV LINE. UP TO A HALF
INCH OF RAIN CAN BE EXPECTED NORTH OF THIS LINE THROUGH TONIGHT...
AND THEN AGAIN LATE SUNDAY NIGHT INTO MONDAY. AREAS SOUTHEAST OF
THE LINE SHOULD SEE LESS THAN A QUARTER INCH THROUGH TONIGHT...THEN
BETWEEN A QUARTER AND HALF INCH INTO MONDAY.
WE HAVE BEEN RATHER DRY OF LATE SO THE RIVER SHOULD BE ABLE HANDLE
THIS PCPN WITH ONLY MINOR RISES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON EDT SUNDAY FOR LMZ846>849.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO NOON EDT SUNDAY
FOR LMZ844-845.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
614 AM EDT SAT APR 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 610 AM EDT SAT APR 6 2013
VERY...VERY COMPLICATED FORECAST WITH ONGOING CHANGES IN THE MODEL
PRECIPITATION LOCATION/AMOUNTS/TYPES.
CURRENTLY...HIGH PRESSURE IS EXITING LOWER MICHIGAN WHILE A 998MB
LOW PRESSURE SYSTEM IS LOCATED IN SOUTHEAST SD. BETWEEN THESE TWO
FEATURES...BROAD LOW-MID LEVEL WARM AIR ADVECTION HAS LEAD TO LIGHT
TO OCCASIONALLY MODERATE SNOW SHOWERS OVER NORTHWEST WISCONSIN AND
MINNESOTA...WHICH HAS SHIFTED INTO SOUTHWESTERN UPPER MICHIGAN OVER
THE LAST COUPLE OF HOURS. DRY LOW LEVEL AIR SEEN ON 00Z KGRB/KINL
SOUNDINGS SEEMS TO HAVE BEEN LIMITING THE INTENSITY OF THE SNOW
THUS FAR...WITH MOST SITES REPORTING VISIBILITIES IN THE 1.5-3MI
RANGE.
THIS FIRST WAVE OF SNOW WILL CONTINUE TO THE EAST-NORTHEAST THROUGH
THE MORNING HOURS AND WITH THE UNDERWHELMING NATURE THUS FAR...IT
SEEMS THE LATEST MODEL TRENDS ARE ON TRACK. EVEN THOUGH THERE IS
PERSISTENT 925-700MB WAA/FGEN AREA THIS MORNING...THE DRY AIR
WILL KEEP SNOW AMOUNTS IN THE 1-3 INCH RANGE AT THE MOST AS THIS
AREA OF SNOW MOVES THROUGH...WITH MOST LOCATIONS SEEING AMOUNTS ON
THE LOW END OF THAT. THERE ARE A FEW CONVECTIVE LOOKING SNOW
SHOWERS FARTHER TO THE SOUTHWEST IN CENTRAL WI/MN THAT HAVE
DEVELOPED OVER THE LAST COUPLE HOURS. THESE MAY HELP FILL IN SOME
OF THE LIGHTER SNOW AREAS...BUT THE COVERAGE WILL LIKELY BE
LIMITED.
THE MORE QUESTIONABLE AND UNCERTAIN PORTION OF THE FORECAST COMES
THIS AFTERNOON INTO TONIGHT...ALTHOUGH LATEST RUNS SEEM TO HAVE THE
SAME IDEA ON A MORE NORTHERLY TRACK TO THE LOW. WV IMAGERY SHOWING
THE MAIN SHORTWAVE WITH THE LOW CURRENTLY ENTERING WESTERN SOUTH
DAKOTA WHILE THE LOW IS IN EASTERN SD. AS THESE TWO FEATURES COME
TOGETHER...EXPECT THE LOW TO INTENSIFY AND LIFT TO THE EAST
NORTHEAST INTO CENTRAL/NORTHERN WI LATE THIS AFTERNOON AND THEN
ACROSS THE MACKINAC STRAITS AROUND 06Z AND JUST NORTH OF THE
GEORGIAN BAY BY 12Z SUNDAY. ALL MODELS NOW HAVE THE IDEA OF WARMER
AIR PUSHING FARTHER NORTH INTO UPPER MICHIGAN THIS AFTERNOON AND
EVENING...AS THE NEXT SWATH OF PRECIPITATION DEVELOPS ON THE NORTH
AND NORTHWEST SIDE OF THE INTENSIFYING LOW. THE FIRST QUESTION MARK
IS IF THERE WILL BE ENOUGH MOISTURE TO LEAD TO PRECIPITATION
REDEVELOPING OVER THE CENTRAL CWA THIS AFTERNOON. WITH THE FIRST
AREA OF PRECIPITATION BECOMING ORIENTATED WEST-EAST ACROSS CENTRAL
LAKE SUPERIOR...THE PERSISTENT WAA FROM 925-700MB AND INCREASING
MOISTURE FROM THE APPROACHING LOW SHOULD LEAD TO SOME SHOWER
REDEVELOPMENT. THE QUESTION IS WHAT TYPE THE PRECIPITATION WILL BE.
WITH THE INCREASING WARM AIR AT THE LOW LEVELS...COULD SEE IT BEING
RAIN OR SNOW OVER THE NORTH HALF OF THE CWA AND RAIN FARTHER SOUTH.
THE LOCATIONS WITH THE MOST WORRIES FOR ACCUMULATIONS WILL BE FROM
THE HIGHER TERRAIN OF MARQUETTE/BARAGA COUNTIES WEST TO GOGEBIC. IN
THIS AREA...BOTH THE COMBINATION OF SURFACE TEMPS IN THE MID 30S
AND A NEARLY ISOTHERMAL TEMPERATURES FOR THE LAST 3-5KFT AROUND 1C
CAUSE CONCERN. JUST A SLIGHT VARIATION IN TEMPERATURES COULD PUSH
PRECIP TO ALL RAIN OR ALL SNOW. WITH THE WARMER TEMPS NEAR THE
SURFACE...HAVE TRENDED MORE TOWARDS A RAIN/SNOW MIX AND EVENTUALLY
TO MOSTLY RAIN AROUND 00Z WHEN THE PEAK WARM AIR IS OVER THE WEST.
SNOW ACCUMULATIONS THEN BECOME A CONCERN...AS THE TEMPS WOULD LIMIT
ACCUMULATION BUT HEAVIER BURSTS COULD PRODUCE A QUICK INCH. FARTHER
TO THE NORTH...EXPECT IT TO MAINLY BE SNOW OVER THE KEWEENAW
PENINSULA.
AS THE LOW TRANSITIONS ENE THROUGH WI AND TOWARDS THE STRAITS OF
MACKINAC TONIGHT...EXPECT A STRONGER AREA OF PRECIPITATION JUST
NORTH OF THE LOW LATE THIS AFTERNOON THROUGH THE EVENING HOURS.
WITH THE WARM AIR EXPECTED IN PLACE OVER THE CENTRAL AND
EAST...WOULD THINK MOST OF THE PRECIP WOULD BE RAIN UNTIL LATE IN
THE NIGHT. OVER THE WEST CENTRAL...SNOWFALL AMOUNTS LARGELY DEPEND
ON TRANSITION TIMING. AN HOUR OR TWO DIFFERENCE COULD MEAN A
SEVERAL INCH DIFFERENCE IN SNOWFALL...AND HAVE WENT ON THE
CONSERVATIVE SIDE WITH ANOTHER 1-3IN TONIGHT FROM THE HIGHER
TERRAIN OF MARQUETTE COUNTY AND WEST. 21Z/03Z SREF PROBABILITIES
AGREE WITH THIS ASSESSMENT OF A BETTER CHANCE OF RAIN BY 00Z AND
THEN CHANGING TO SNOW FROM WEST TO EAST...SO HAVE DEFINITELY
TRENDED THE FORECAST IN THAT DIRECTION. BEHIND THE LOW...900-875MB
TEMPS FALLING TO AROUND -7C LEADS TO ENOUGH LAKE INSTABILITY TO
PRODUCE LAKE ENHANCED SNOWFALL OVER THE NORTHWEST FAVORED LOCATIONS
OVER WESTERN UPPER MICHIGAN AFTER MIDNIGHT AND INTO THE OVERNIGHT
HOURS...BEFORE THE DEEPER MOISTURE QUICKLY DEPARTS FROM WEST TO EAST
AND QUICKLY LOWERS INVERSION HEIGHTS TO 3KFT BY 12Z ON SUNDAY.
ONE INTERESTING ITEM IS THE AMOUNT OF WARM AIR THAT THE LATEST RAP
RUNS PUSH INTO THE AREA. IT HAS KMNM REACHING THE LOWER 50S AND
KIMT/KESC IN THE MID 40S AND EVEN SOME OF KIWD TO KSAW NEARING 40
DEGREES. THIS MAY NOT BE TOO CRAZY...WITH LIMITED DEEP MOISTURE
FARTHER TO THE SOUTHWEST WITH MAINLY MID/HIGH CLOUDS OVER SOUTHERN
WI AND SOUTHERN MN. THIS WOULD LEAD TO A FILTERED SUNSHINE AND
ALLOW MORE HEATING TO REACH THE AREA. HAVE ADJUSTED TEMPS UP SOME
FOR TODAY TO ACCOUNT FOR THIS...BUT NOT AS HIGH AS THE RAP IS
INDICATING.
SO...WHAT TO DO WITH THE HEADLINES. WILL LEAVE THE ADVISORIES AS IS
FOR THE MORNING HOURS DUE TO THE SNOW MOVING INTO THE
AREA...ALTHOUGH THERE IS A GOOD CHANCE MANY LOCATIONS WON/T SEE
ADVISORY TOTALS. FOR AREAS OVER THE SOUTH CENTRAL AND EAST...MOVED
UP ENDING TIME TO MATCH WHEN INITIAL SNOW IS DONE AND EXPECTED
CHANGE OVER TO RAIN. OVER THE WEST...THERE WAS ENOUGH UNCERTAINTY
TO LEAVE THEM AS IS...ALTHOUGH DID EXTEND THE TIME TO BE A LITTLE
LATER. NRN HOUGHTON AND KEWEENAW IS ONE AREA WHERE THERE IS SOME
CONCERN FOR WARNING SNOW AMOUNTS DUE TO THEM STAYING MAINLY SNOW
AND THE INITIAL WAA PRECIPITATION PIVOTING THERE THIS
AFTERNOON/EVENING. ONLY ABOUT 5-6 21Z SREF MEMBERS THAT GET SNOWFALL
AMOUNTS OVER 6IN IN THAT AREA THROUGH TONIGHT. WITH DAYTIME
HEATING LIKELY LIMITING AMOUNT OF ACCUMULATION ON ROADWAYS AND
LIMITED CONFIDENCE ON 6IN...WILL LEAVE AT ADVISORY FOR NOW ALTHOUGH
DAY SHIFT WILL NEED TO MONITOR TRENDS AND POTENTIALLY UPGRADE TO
WARNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 610 AM EDT SAT APR 6 2013
MODELS STILL EXHIBIT GREAT VARIABILITY AND UNCERTAINTY FOR THE
EXTENDED PERIOD OF THE FCST. MUCH OF UNCERTAINTY HINGES ON THE
STRENGTH OF THE LINGERING ERN CANADA TROF UNDER WEAKENING NEGATIVE
AO/NAO WHICH MEDIUM RANGE MODELS ARE HANDLING DIFFERENTLY.
ON SUN...SFC HIGH PRES WILL NOSE INTO THE UPPER LAKES BEHIND THE LOW
PRES SYSTEM...BRINGING AN INFLUX OF DRIER AIR. DAYTIME TEMPS SHOULD
RECOVER WELL INTO THE 30S/LWR 40S IN THE AFTN WITH SOME INCREASE IN
SUNSHINE DURING THE DAY.
SUN NIGHT AND MON...00Z GFS NOW COMING ON BOARD WITH THE 00Z GEM-NH
AND 12Z/00Z ECMWF SHOWING INITIAL SHORTWAVE EJECTING ENE TOWARD THE
GREAT LAKES AHEAD OF DEVELOPING WRN CONUS TROF. WITH PRECIPITABLE
WATER VALUES RISING TO 160-180 PCT OF NORMAL AND STRENGTHENING 290K
ISENTROPIC ASCENT...AND 800-700 MB FGEN FORCING IN RIGHT ENTRANCE
REGION OF STRENGTHENING 100KT UPR JET MAX...WOULD EXPECT GOOD CHC OF
PCPN MOVING ACROSS THE FCST AREA. BASED ON 850MB TEMPS/1000-850MB
THICKNESS...WILL TREND PTYPE TO MOSTLY RAIN ACROSS ROUGHLY THE SE
HALF AND RAIN/SNOW MIX NW. INCLUDED FZRA SUN NIGHT INTO EARLY MON AS
WELL WHERE TEMPS WERE STILL SUBFREEZING. GIVEN HIGH PW
VALUES...THERE MAY BE A THREAT FOR MODERATE TO HEAVY RAIN AS THIS
SHORTWAVE MOVES THROUGH THE AREA. EXPECT PCPN TO TAPER OFF MON
EVENING AS FGEN FORCING WEAKENS.
WILL CONTINUE TO FAVOR A ECMWF/UKMET BLEND SOLN FOR TUE/WED FCST AS
THOSE MODELS APPEAR TO BETTER FIT THE PATTERN OF THE LINGERING BUT
WEAKENING NEGATIVE NAO WHICH HOLDS TROF IN OVER SE CANADA. IF THIS
SOLN WORKS OUT...DRY WEATHER SHOULD BE THE RULE TUE AND POSSIBLY
THRU WED AFTN BUT AGAIN CONFIDENCE WILL BE LOW UNTIL MODELS SORT OUT
TIMING/PLACEMENT OF SHORTWAVES LIFTING OUT OF THE WRN CONUS TROF. AS
MAIN PIECE OF ENERGY IN THE WRN TROF LIFTS NORTH TOWARD THE UPPER
GREAT LAKES...MODELS STILL POINT TOWARD EPISODE OF MDT TO POSSIBLY
HVY PCPN INTO UPPER MI AT SOME POINT WED-FRI. IF THE COLDER ECMWF IS
RIGHT...ANOTHER SIGNIFICANT SNOW COULD BE POSSIBLE FOR THE FCST
AREA...WHILE IF THE WARMER GFS AND 00Z GLOBAL GEM THERMAL FIELDS
VERIFY...MOSTLY RAIN WOULD BE EXPECTED SE HALF TO MOSTLY SNOW NW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 128 AM EDT SAT APR 6 2013
VFR CONDITIONS WILL CONTINUE UNTIL LATE TONIGHT AS LOW LEVEL DRY AIR
WILL BE SLOW TO BE OVERCOME. CONDITIONS WILL RAPIDLY DETERIORATE AS
A STORM SYSTEM COMES IN AND BRINGS WARM ADVECTION PRECIPITATION TO
THE AREA AND WILL GO RAPIDLY DOWN TO IFR/LIFR CONDITIONS BY MORNING.
LOOKS TO BE A LULL BY MID MORNING INTO EARLY AFTERNOON WHERE
CONDITIONS WOULD GO TO MVFR/IFR. WRAPAROUND MOISTURE COMES IN LATE
IN THE AFTERNOON AND HEAVIER SNOW WOULD AGAIN BREAK OUT TO IFR/LIFR
VIS LATE INTO THE TAF PERIOD. COULD BE SOME SLEET MIXED IN WITH THE
PCPN AT SAW AND IWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 610 AM EDT SAT APR 6 2013
A LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES REGION TODAY
AND TONIGHT WILL LEAD TO INCREASING SOUTHEASTERLY WINDS
TODAY...ESPECIALLY OVER EASTERN LAKE SUPERIOR WHERE GUSTS WILL
APPROACH 30KTS AND THERE COULD EVEN BE A FEW GALE FORCE GUSTS TO
35KTS. AS THE LOW SHIFTS EAST TONIGHT...WINDS WILL SHIFT TO THE
NORTHWEST UP TO 25KTS. HIGH PRESSURE WILL LEAD TO DIMINISHING WINDS
ON SUNDAY. NORTHERLY WINDS WILL INCREASE TO 20KTS ON MONDAY AS THE
PRESSURE GRADIENT INCREASES BETWEEN A HIGH IN CENTRAL CANADA AND A
LOW MOVING THROUGH THE LOWER GREAT LAKES. THE HIGH SHOULD LEAD TO
LIGHT NORTHEASTERLY WINDS ON TUESDAY...BUT ANOTHER LOW PRESSURE
SYSTEM POTENTIALLY MOVING THROUGH THE GREAT LAKES ON WEDNESDAY INTO
THURSDAY COULD LEAD TO STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ006-
013-014-085.
WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MIZ007.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ SUNDAY FOR
MIZ001>005-009-010-084.
WINTER WEATHER ADVISORY UNTIL 11 AM CDT THIS MORNING FOR MIZ011-
012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
714 PM CDT SUN APR 7 2013
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 306 PM CDT SUN APR 7 2013
SURFACE RIDGE MOVES EAST TONIGHT ALLOWING NEXT SHORT WAVE TO MOVE
ACROSS THE AREA TONIGHT INTO MONDAY MORNING. THE 09Z SPC SREF ONE
HOUR THUNDER GUIDANCE DOES INCREASE AN AREA OF INCREASING PROBS FROM
SOUTH CENTRAL MN INTO WEST CENTRAL WI LATE THIS EVENING INTO MONDAY
MORNING. BEST LI`S AND H85 LI GRADIENT LIES ACROSS SOUTHERN
MN...AND AS SYSTEM MOVES THROUGH VARIOUS HIRES MODELS INDICATE
HIGHER REFLECTIVITY ASSOCIATED. WILL CONTINUE TO MENTION ISOLD
THUNDER IN THIS REGION. CRITICAL THICKNESS BECOMES DEFINED MAINLY
NORTH AND WEST OF THE CWA...BUT THE POSSIBILITY OF A RAIN/SNOW MIX
REMAINS IN THE FAR NORTHWEST PERIPHERY OF THE CWA LATE TONIGHT INTO
MONDAY MORNING. NO ACCUMULATION EXPECTED HOWEVER.
AREA REMAINS IN BETWEEN SYSTEM FOR MOST OF MONDAY...AS UPPER TROUGH
ORGANIZES AND DEVELOPS SURFACE CYCLONE OVER THE COLORADO ROCKIES
REGION. MAY SEE A SHOWER/SPRINKLE INTO MONDAY AFTERNOON...AS UPPER
JET EXITS TO THE NORTHEAST. WILL HOLD ONTO SOME CHANCE POPS.
SURFACE WARM FRONT REMAINS OVER IOWA DURING THIS PERIOD...WITH HIRES
NNM WRF BACKING AWAY FROM SEVERE STORM DEVELOPMENT (SEVERE RIGHT
MOVER) VICINITY OF THE WARM FRONT LATE MONDAY AFTERNOON. HIGH
TEMPERATURES SHOULD BE LIMITED DUE TO CLOUDS AGAIN MONDAY
AFTERNOON. MAY BE TOO WARM NEAR THE MN/IA BORDER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 306 PM CDT SUN APR 7 2013
THE FORECAST GETS EVEN MORE INTERESTING FROM MONDAY NIGHT INTO THE
MIDDLE OF NEXT WEEK...AS THE FOUR CORNERS REGION MID/UPPER TROUGH
EJECTS NORTHEAST TOWARD THE CENTRAL CONUS AND PUSHES THE ATTENDANT SOUTHERN
PLAINS SURFACE TROUGH TOWARD SOUTHERN LAKE MICHIGAN. MODELS ARE
STILL NOTABLY VARIABLE WITH RESPECT TO THE SURFACE LOW
TRACK...ALTHOUGH THE 07.12Z NAM DID TREND SOUTHWARD TOWARD THE
GFS AND ECMWF. FOR NOW...WILL LEAN TOWARD THE GFS ENSEMBLE
MEAN...WHICH TRACKS THE LOW ACROSS SOUTHERN IA AND NORTHERN MO
TOWARD SOUTHERN LAKE MI. THIS WOULD PLACE CENTRAL MN/WI IN A VERY
FAVORABLE LOCATION FOR A PROLONGED PERIOD OF MEASURABLE
PRECIPITATION FROM TUESDAY THROUGH WEDNESDAY NIGHT...MUCH OF WHICH
COULD FALL AS SNOW. PLOWABLE SNOWFALL LOOKS LIKELY FOR AT LEAST A
PORTION OF THE FORECAST AREA. FLOODING WILL ALSO BE A
THREAT...GIVEN EXPECTED LIQUID PRECIP AMOUNTS IN THE ONE HALF TO
NEAR 1.5 INCH RANGE OVER THE TWO DAY PERIOD.
THURSDAY WILL BRING GRADUALLY ENDING PRECIPITATION AS THE LOW
SHIFTS EAST...ALTHOUGH THAT WILL SIGNAL COLDER TEMPERATURES AS
HIGH PRESSURE FILTERS IN. THURSDAY HIGHS WILL BE MOSTLY IN THE MID
30S...WITH LOWS FALLING INTO THE 20S ON THURSDAY NIGHT.
FRIDAY WILL BRING CONTINUED COOL BUT DRY WEATHER...WITH HIGHS
GENERALLY IN THE 35 TO 40 DEGREE RANGE.
YET ANOTHER SYSTEM APPROACHES THIS WEEKEND...AS DEPICTED BY BOTH
GFS AND ECMWF MODELS. THERE ARE STILL TEMPORAL DIFFERENCES...BUT
SUNDAY LOOKS MORE LIKELY TO BE THE WET DAY OF THE WEEKEND. THERMAL
PROFILES INDICATE THIS WILL BE ANOTHER EVENT WITH A WINTRY MIX OF
PRECIPITATION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 714 PM CDT SUN APR 7 2013
PRECIPITATION ALREADY RETURNING TO WRN MN AT TAF ONSET. FOR
PRECIP...FOLLOWED A RAP/HRRR/NAM TIMING AS LLJ AND WARM ADVECTION
INDUCED BAND OF PRECIP MOVES ACROSS THE REGION THIS EVENING. BASED
ON THAT MODEL BLEND...EXPECT 3 BANDS ACROSS THE CENTRAL CONUS THIS
EVENING...FARGO AND POINTS ENE...SW MN INTO NW WI...AND THE
HEAVIEST BAND FROM NE KS ACROSS NRN MO. WITH THE MIDDLE BAND...
RWF/MSP/STC/RNH LOOK TO BE RIGHT IN THE MIDDLE OF IT...WITH
EAU/AXN LIKELY SITTING ON THE EDGE. THIS WILL BE QUICK
MOVING...WITH RAIN BASICALLY OUT OF MN AROUND 9Z AND THE EAU AREA
BY 15Z. AS FOR CLOUDS...MVFR CIGS QUICKLY BLEW OUT OF THE AREA
THIS AFTERNOON...AND ONLY MVFR CONDS CURRENTLY BEING OBSERVED ARE
WITH REDUCED VSBYS WITH RAIN OUT WEST. AS A RESULT...SLOWED SOME
THE ARRIVAL OF THE LOW MVFR/IFR CIGS. IN FACT...THE RAP WOULD
INDICATE RWF/MSP/RNH/EAU MAY NOT SEE MUCH IN THE WAY OF SUB VFR
CIGS UNTIL LATE MORNING AT THE EARLIEST. BASICALLY...THE RAP IS
HOLDING ANY WIDESPREAD LOW CIGS TO NORTH OF A WARM FRONT AT 925-850
MB THAT IS NEAR A RWF/MSP/EAU LINE AT 15Z. INSTEAD...WENT WITH THE
NAM IDEA...THAT MOISTENING OF THE ATMO BEHIND THE RAIN WILL ALLOW
CIGS TO FALL INTO THE IFR/LOW MVFR RANGE. IN ADDITION...MOIST NE
LOW WINDS SHOULD PROMOTE THE DEVELOPMENT OF HZ/BR AS WE ADVECT
MOISTURE DOWN FROM THE DWINDLING SNOW PACK NORTH OF I-94. LIKE
TODAY...MAY ALSO SEE A BRIEF VFR WINDOW OUTSIDE OF CENTRAL MN IN
THE AFTERNOON IN THE WAKE OF THIS FIRST WAVE...THOUGH PLAYED
THINGS DOWN THE PESSIMISTIC ROUTE FOR NOW.
KMSP...ONLY MADE A MINOR TIMING CHANGE TO GOING TAF WITH PRECIP
ONSET. EXPECTING HEAVIEST RAIN TO FALL BETWEEN 4Z AND 7Z...WITH
PRECIP ALL BUT DONE BY 9Z. THUNDER POTENTIAL LOOKS VERY
LOW...THOUGH AN ISOLATED RUMBLE OF THUNDER CAN NOT BE RULED
OUT...BUT ANY EXPECTED COVERAGE IN TSRA IS NOWHERE NEAR HIGH ENOUGH
TO INCLUDE IN TAF. GIVEN THE ADDED MOISTURE AFTER THE
RAIN...FOLLOWED THE IDEA OF THE GFSLAMP WITH IFR CIGS DEVELOPING
BY THE LATE MORNING...THOUGH DELAYED THINGS BASED ON HOW SLOW THE
RAP/HRRR BRING THE LOWER CIGS IN BEHIND THE RAIN. CONFIDENCE IS
FAIRLY HIGH THAT AT THE VERY LEAST...CIGS WILL BE BELOW 1700 FT
MUCH OF MON MORNING. MAY ALSO HAVE A PERIOD IN THE AFTERNOON WHEN
CIGS GO VFR...BUT CONFIDENCE LOW ON THAT OCCURRING AT THE MOMENT.
MSP LOOKS TO REMAIN DRY UNTIL THE NEXT WAVE MOVES IN LATE MONDAY
NIGHT INTO TUESDAY MORNING.
/OUTLOOK FOR KMSP/
TUE...IFR CIGS/VSBYS WITH -RA. -RASN POSSIBLE TUE NIGHT. WIND NE
15G25 KTS.
WED...IFR CIGS/MVFR VSBYS WITH -RASN BR. WIND NE 10-15KTS.
THU...MVFR OR LOWER CIGS/VIS WITH CHANCE -SN. BCMG VFR LATE. WIND
NNE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DWE
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
917 PM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 904 PM CDT SUN APR 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS BEEN ONGOING IN A NORTHWARD
LIFTING FRONTAL ZONE DRAPED ACROSS THE MIDSECTION OF THE CWA THIS
EVENING. LATEST RUC DATA ALONG WITH THE 4KM NSSL NMM WRF INDICATE
THE POTENTIAL FOR THE STORMS TO CONTINUE TO PERCOLATE IN THE
AFOREMENTIONED FRONTAL ZONE...WITH LOCALIZED MUCAPE VALUES AOA
200-400 J/KG. STORMS HAVE THUS FAR REMAINED SUB-SEVERE...HOWEVER
HAIL UP TO NICKEL SIZE HAS BEEN REPORTED WITH SOME OF THE STRONGER
STORMS OVER THE STL METRO EAST.
HAVE ADJUSTED TIMING OF PRECIPITATION THIS EVENING...ESPECIALLY
OVER THE WESTERN HALF OF THE CWA...WITH TWO MAIN AREAS OF CONCERN.
THE FIRST IS WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY THAT HAS
OVERSPREAD NW MO AND EASTERN KS THIS EVENING...EXPECTED TO MOVE
INTO CENTRAL AND NE MO THROUGH THE EARLY OVERNIGHT HOURS ON THE
NOSE OF AN INTENSIFYING LLJ. THE SECOND AREA OF CONCERN IS A
POTENT STORM MOVING THROUGH SOUTH CENTRAL MO WHICH HAS MAINTAINED
INTENSITY AS IT MARCHES EASTWARD. MODELS FORECAST THE STORM TO
WEAKEN PRIOR TO IMPACTING OUR SOUTHERN COUNTIES...THOUGH THE FACT
THAT IT HAS CONSISTENTLY PRODUCED GOLFBALL SIZED HAIL AND DOES NOT
APPEAR TO BE DIMINISHING IN STRENGTH HAS PIQUED OUR INTEREST A
BIT. MAY HAVE TO FURTHER ADJUST POPS OVER SOUTHERN COUNTIES IF
THIS STORM MAINTAINS ITS INTENSITY AND CURRENT TRACK. WILL
CONTINUE TO MONITOR THIS FEATURE CLOSELY.
OTHERWISE...THE FORECAST HAS REMAINED ON TRACK THIS
EVENING...WITH ONLY A FEW CHANGES TO TEMPERATURE AND DEWPOINT
TRENDS TO ACCOUNT FOR LOCATIONS WITH RAIN COOLED AIR DUE TO STORM
ACTIVITY TONIGHT.
JP
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 PM CDT SUN APR 7 2013
WHILE THE PRECIPITATION CHANCES ARE EXPECTED TO RAMP UP CONSIDERABLY
TONIGHT...THE EXACT DETAILS ARE STILL A TAD UNCLEAR. THIS IS IN
PART DUE TO DIFFERENCES AMONGST THE DETERMINISTIC MODELS AND
CONVECTION ALLOWING MODELS WITH RESPECT TO THE CONVECTIVE
EVOLUTION AND TIMING. THE OVERALL SCENARIO REMAINS UNCHANGED. A
QUASI-STATIONARY BOUNDARY NOW STRETCHES FROM NW MO THROUGH CENTRAL
MO WHERE IT THEN TAILS EASTWARD THRU THE ST LOUIS AREA INTO SE
ILLINOIS. MOISTURE ADVECTION TODAY AND HEATING HAS RESULTED IN A
WEAKLY UNSTABLE AIR MASS TO THE SOUTH OF THE BOUNDARY AND A GOOD
DEAL OF AGITATED CU IS NOW PRESENT. EVEN A FEW SPOTTY SHOWERS HAVE
DEVELOPED SSE OF ST LOUIS. THIS BOUNDARY IS FORECAST TO GRADUALLY
RETREAT NORTHWARD TONIGHT WHILE THE LOW AMPLITUDE SHORT WAVE NOW
OVER CENTRAL KS MOVES EASTWARD THRU THE AREA IN CONJUNCTION WITH
AN INTENSIFYING AND VEERING SWLY LLJ. ALL THE STRONG FORCING VIA
THE SHORTWAVE AND LLJ ARE FOCUSED ALONG AND NORTH OF I-70 WITHIN
THE COOL SECTOR NORTH OF THE RETREATING BOUNDARY. MY BEST GUESS IS
THAT THERE COULD BE SEVERAL WAVES OF ORGANIZED CONVECTION. THE
GROWING CONVECTION PRESENTLY IN SE KS MAY PUSH ENE INTO CENTRAL MO
THIS EVENING WHILE ADDITIONAL ISOLATED-SCATTERED CONVECTION COULD
ATTEMPT TO DEVELOP ALONG AND JUST SOUTH OF THE FRONT ZONE. THEN LATER
THIS EVENING AND TONIGHT ONE OR MORE CONVECTIVE CLUSTERS SHOULD
DEVELOP ACROSS NE KS AND NW MO AND MOVE EASTWARD IN CONJUNCTION
WITH THE VEERING LLJ AND MIGRATING SHORTWAVE TROF. WITH PLENTLY OF
DEEP LAYER SHEAR PRESENT...DEPENDING ON THE CAPE EVOLUTION...A FEW
OF THESE STORMS ACROSS CENTRAL MO COULD BE SEVERE.
I THINK BY DAYBREAK MONDAY...MOST OF THE OVERNIGHT CONVECTION
SHOULD BE NE OF THE CWA AS THE SHORTWAVE IS WELL TO THE EAST AND
THE LLJ IS STRONGLY VEERED TO THE WEST SOUTHWEST...HOWEVER I CANT
RULE OUT SOME SCATTERED TRAILING STORMS ALONG THE LLJ AXIS AND ANY
RESIDUAL BOUNDARIES. EVEN IF THIS IS PRESENT...I WOULD THINK IT
SHOULD HAVE EXITED THE AREA BY MID-LATE MORNING. THEREAFTER THE
EML BUILDS IN STRONGLY THROUGH THE AFTERNOON AND RESULTS IN
SUBSTANTIAL CAPPING OF THE WARM SECTOR...WITH THE FRONT LIFTING
INTO IOWA. THUS AFTERNOON THUNDERSTORM CHANCES LOOK MORE ISOLATED
BARING ANY LINGERING BOUNDARIES.
GLASS
.LONG TERM...(MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 244 PM CDT SUN APR 7 2013
THE LAST FEW DAYS THE ECMWF MODEL HAS BEEN AN OUTLIER WITH A MORE
SOUTHWARD EAST-WEST ORIENTED BOUNDARY POSITION ACROSS NORTHERN
MISSOURI FROM MONDAY THROUGH TUESDAY NIGHT. ON THE LAST 2 RUNS
HOWEVER THE ECMWF HAS JOINED THE REST OF THE MODELS WITH A MORE
NORTHWARD BOUNDARY POSITION ACROSS SOUTHERN IOWA OR THE MO/IA
BORDER. THIS WOULD SUGGEST LESSER PRECIPITATION CHANCES ACROSS
NORTHERN MISSOURI DUE TO THE LACK OF A FOCUSING BOUNDARY...AND AS
THE WARM SECTOR IS EXPECTED TO BE CHARACTERIZED BY A DECENT CAP
FOR SURFACE BASED STORMS UNTIL LATE TUESDAY NIGHT. THE MOST ACTIVE
PERIOD IS STILL EXPECTED TO BE THE LATE TUESDAY NIGHT INTO
WEDNESDAY TIME FRAME WHEN THE DEEP LARGE SCALE TROF AND ATTENDANT
COLD FRONT PROGRESSES EASTWARD INTO THE NATIONS MIDSECTION. I
STILL BELIEVE THE SCENARIO I LAYED OUT YESTERDAY IS QUITE
LIKELY... THAT THE ORGANIZED SEVERE CONVECTION ACROSS THE PLAINS
ON TUESDAY AFTERNOON WILL GROW UPSCALE INTO A LINE/QLCS AND SHIFT
EASTWARD INTO THE AREA OVERNIGHT TUESDAY INTO WEDNESDAY MORNING.
IT NOW APPEARS THAT ADDITIONAL STORMS COULD DEVELOP THROUGHOUT THE
DAY ON WEDNESDAY AND WED EVENING AHEAD OF THE COLD FRONT MOVING
ACROSS THE AREA...BUT THIS WILL BE LARGELY DEPENDENT ON STABILIZING
EFFECTS OF ANY PREVIOUS CONVECTION. STRONG DEEP LAYER SHEAR AND
AMPLE INSTABILITY SUPPORTS A SEVERE WEATHER THREAT PER THE SPC
OUTLOOKS.
IN THE WAKE OF THE MIDWEEK SYSTEM THERE WILL BE A GOOD COOL DOWN
THUR-FRIDAY TO BELOW AVERAGE TEMPS WITH BROAD CYCLONIC FLOW ALOFT
AND HIGH PRESSURE DOMINATING IN THE WAKE OF THE WEAKENING
PROGRESSIVE LONGWAVE TROF. THE FLOW ALOFT LOOKS TO TRANSITION TO
QUASI-ZONAL BY WEEKEND WITH THE SURFACE HIGH RETREATING...LEADING
TO MODERATING TEMPERATURES.
GLASS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 648 PM CDT SUN APR 7 2013
FRONTAL BOUNDARY REMAINS STALLED JUST SOUTH OF I-70 EARLY THIS
EVENING. SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED NEAR
BOUNDARY AND ARE TRACKING TO THE NORTHEAST...THOUGH BEST CHANCES
OF STORMS WILL BE LATER TONIGHT AS LOW LEVEL JET CRANKS UP OVER
CENTRAL/NORTHEAST MO...WEST CENTRAL IL AND FRONT MOVES BACK TO THE
NORTH. PCPN TO COME TO AN END BETWEEN 12Z AND 15Z...WITH MVFR CIGS
LIFTING TO VFR AND SCATTERING OUT BY MONDAY AFTERNOON. AS FOR
WINDS...SOUTHEAST WINDS TO VEER TO THE SOUTH AND PICKUP AS
FRONTAL BOUNDARY LIFTS NORTH. WINDS TO REMAIN SOUTHERLY THROUGH
REST OF FORECAST PERIOD.
SPECIFICS FOR KSTL...FRONTAL BOUNDARY REMAINS STALLED JUST SOUTH
OF I-70 EARLY THIS EVENING. SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED NEAR BOUNDARY AND ARE TRACKING TO THE
NORTHEAST. COULD SEE SOME SCATTERED SHOWERS/ISOLATED THUNDERSTORM
OVER KSTL THIS EVENING. BEYOND THAT HARD TO PIN DOWN HOW FAR EAST
AND SOUTHEAST COMPLEX MAKES IT AS IT TRACKS NORTHEAST...MAINLY
OVER CENTRAL/NORTHEAST MO. PCPN TO COME TO AN END BY 12Z...WITH MVFR
CIGS LIFTING TO VFR AND SCATTERING OUT BY 19Z MONDAY. AS FOR
WINDS...SOUTHEAST WINDS TO VEER TO THE SOUTH AND PICKUP AS FRONTAL
BOUNDARY LIFTS NORTH AROUND 06Z MONDAY. WINDS TO REMAIN SOUTHERLY
THROUGH REST OF FORECAST PERIOD.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
655 PM CDT Sun Apr 7 2013
.MESOSCALE DISCUSSION...
Issued at 654 PM CDT SUN APR 7 2013
Convection is starting to expand across cntrl/ern KS in response to a
strengthening low-level jet. This jet will continue to intensify and
nose into ern KS/wrn MO through the late evening, and into northern
MO overnight. Convergence ahead of the jet will be adequate for
continued upscale growth of this convection into the KC metro through
10 PM and into northern/eastern parts of the forecast area after
midnight. Instability through this time will be decreasing so severe
threat should be somewhat marginal. In fact, latest RAP soundings
indicate surface dewpoints around 60F needed for any surface-based
instability at all, and this may be hard to achieve given upstream
dewpoints only in the mid/upper 50s. Still, good theta-e advection in
the LLJ combined with increasing low-level helicity and adequate
deep-layer shear could lead to a threat for large hail in elevated
storms through the late evening.
&&
.SHORT TERM...(This Evening through Monday Afternoon)
Issued at 411 PM CDT SUN APR 7 2013
This Evening and Tonight:
Modest moisture advection continues to raise dewpoints into the
lower to mid 50s across our southwestern zones, generally along and
south of Highway 50. Cloud cover has inhibited warmer temperatures
but we are still seeing afternoon temperatures in the low to mid
70s. A nebulous/weakly defined warm front, evident by a slight wind
shift and greater dewpoints over southeastern KS and west central
MO.
Convection has initiated in south central KS and the anticipation is
that this area of storms will propagate eastward and impact mainly
portions of southeast KS and southwest MO. There is a tight gradient
of instability along and south of the forecast area and given the
supercellular structure of the initial convection and it`s eastward
movement there is enough uncertainty to keep a watch south of the
area for now. If instability can build more northward into the
forecast area, there is ample deep layer shear to support organized
convection, likely in the form of supercells initially, with a
threat for large hail and strong winds.
Additional convection may develop later this evening over central to
eastern KS and move eastward into extreme eastern KS and MO during
the overnight hours. The severe threat looks more marginal with those
storms, should they develop, but they could still produce marginally
severe hail and strong winds. These storms would likely track
eastward along the instability gradient/warm front, which would
likely generally run from east to west along the I-70 corridor. So
strong to possibly severe storms may affect the region during the
overnight hours with the most likely timing being around midnight,
give or take a few hours either way.
Monday:
With the area likely to be in the wake of overnight convection, low
clouds possibly lingering into the late morning and afternoon hours,
have trimmed precipitation chances considerably and confined them to
our eastern zones. Cloud cover will likely keep temperatures from
getting as warm as the previous two days, but we will still see
highs in the lower 70s. The exception may be in our northwest were
cloud cover may diminish earlier leading to longer sun.
.LONG TERM...(Monday Evening through Sunday)
Issued at 411 PM CDT SUN APR 7 2013
Monday Evening into Tuesday...
With a front in the vicinity of our Iowa border, expectations are
that the nocturnal low level jet will kick off overnight convection.
Models are not shy about advertising several hundred J/KG of MUCAPE
advecting over the front as the jet kicks in, but soundings point at
thunderstorms being elevated in nature, so the severe threat is
looking only marginal. However, with precipitable water values of 1
inch plus, heavy rain could be an issue with any storms that
develop.
As the day arrives Tuesday, convection will likely be shifting out
of our region from the overnight hours, though some lingering
activity might stick around through mid-morning. Much of the day
should be rather nice, with warm southerly winds prevailing helping
support highs in the upper 60s and 70s. However, soundings still show
the region remaining rather capped through the day, so currently not
expecting any additional daylight thunderstorm activity in our
forecast area. However, with a cold front moving in our direction
through Kansas, thoughts are that central and north central Kansas
could have a lot of afternoon activity, which would congeal and shift
east into us Tuesday night.
Tuesday Night into Wednesday...
Expecting the main thrust of the strong to severe storms to arrive
in the evening to overnight hours of Tuesday night. Convection from
the daylight hours of Tuesday will likely be closing in on, or have
reached, our forecast area by the evening hours. Support from the
upper level dynamics and surface front will provide us with plenty
of opportunity to keep convection going into and through the
overnight hours. The nocturnal jet ahead of the advancing front will
have its opportunity to enhance the convective potential late
Tuesday night as the front moves through bringing the threat of
severe thunderstorms to the entire region.
The slow frontal progress could keep rain going into and through the
day Wednesday, with post frontal showers across the far northern and
western reaches of the forecast area. There could be a small window
of opportunity for more thunderstorms in the warm sector ahead of the
front, east of a west central to northeast Missouri line during the
morning and afternoon hours.
Thursday through Sunday...
Cooler weather will great this period thanks to the cold front that
moved though the region Tuesday night/Wednesday. The axis of the
west CONUS trough will shift east through Missouri Thursday night,
likely providing us with some of the coolest temperatures of the
work week as the center of the cool Canadian high slides across.
This will likely make Thursday night lows possibly below
freezing over a large portion of northern Missouri and eastern
Kansas Thursday night, with more limited freezing conditions again
Friday night. However, the cool surface high that will be dominating
the Plains will quickly shift east, allowing a warming return flow to
reestablish itself by Saturday. This return flow will allow near
normal temperatures to prevail again for next weekend.
As for precipitation, not a lot is expected in these outer periods.
Flow across our section of the Plains States continues to look
rather flat and zonal at the tail end of the work week and through
the weekend, with only a hint of a shortwave moving across the
Plains next weekend. This should keep us dry through the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 654 PM CDT SUN APR 7 2013
Convection is growing in coverage and intensity over central/eastern
KS at this time, and this trend should continue through the evening.
Storms could become fairly widespread across ern KS/wrn MO over the
next few hours with the peak occurring near KC around 02Z to 04Z.
Some of the stronger storms could produce hail. Cig forecast after
this time becomes tricky, but chances for prolonged MVFR cigs appear
high enough to maintain a prevailing group through at least sunrise.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
MESOSCALE...Hawblitzel
SHORT TERM...CDB
LONG TERM...Cutter
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS BILLINGS MT
921 PM MDT SUN APR 7 2013
.SHORT TERM...VALID FOR MON AND TUE...
ACTIVE WEATHER TONIGHT AS DIFLUENT FLOW INCREASING OVER OUR AREA
IN RESPONSES TO A LARGE TROUGH OF LOW PRESSURE DEEPENING OVER THE
WEST COAST. THIS HAS LED TO ISOLATED THUNDERSTORMS WITH BRIEF
HEAVY RAIN AND PEA SIZE HAIL THIS EVENING FROM HYSHAM WEST.
THUNDERSTORMS HAVE ENDED BUT SHOWERS WILL CONTINUE OVER THE AREA
FOR SEVERAL MORE HOURS. COLD FRONT HAS ALREADY PUSHED THROUGH
BILLINGS THIS EVENING WITH COLD AIR BEGINNING TO ENTER OUR
NORTHERN ZONES. TEMPERATURES HAVE ALREADY FALLEN TO THE LOWER 30S
IN JUDITH GAP WITH LIGHT SNOW FALLING THERE FOR THE PAST COUPLE OF
HOURS.
CHANGES TO GOING FORECAST WAS TO INCREASE POPS ACROSS OUR
NORTHERN ZONES THIS EVENING AS STRONG FRONTOGENESIS MOVES IN. 00Z
NAM CONTINUES TO TAKE THIS FORCING EAST TONIGHT. MODELS CONTINUE
TO LOOK OVERDONE WITH QPF VALUES AND WILL LEAN TOWARD THE NAM12
SOLUTION. WILL ALSO CONTINUE THE TREND OF LIGHT SNOW AND LIGHT
ACCUMULATIONS ALONG AND SOUTH OF A LINE FROM LIVINGSTON TO
BILLINGS TO EKALAKA. DID RAISE POPS AND SNOW AMOUNTS OVER THE
SOUTHWEST MOUNTAINS AS MOIST WESTERLY FLOW WILL CONTINUE OVER THAT
AREA THROUGH MORNING WITH ADDITIONAL 4 TO 5 INCHES OF NEW SNOW
POSSIBLE. RICHMOND
WINTER WEATHER EVENT COMING TONIGHT INTO TUESDAY...WITH STRONG
COLD FRONTAL PASSAGE LATER TONIGHT. MUST CONTINUE TO STRESS GREAT
UNCERTAINTY IN THE DETAILS.
THERE ARE TWO PHASES WITH THIS EVENT. PHASE ONE INVOLVES
FRONTOGENETIC PCPN AS PACIFIC SHORTWAVE INTERACTS WITH CANADIAN
COLD FRONT...BEGINNING LATER THIS EVENING AND LASTING INTO
MONDAY. THIS WILL NOT BE AN UPSLOPE EVENT AS PCPN WILL BE DRIVEN
AT THE MID LEVELS...WITH BEST FORCING ACROSS OUR NORTH. TREMENDOUS
MODEL DIFFERENCES EXIST HERE...WITH NAM AND RAP KEEPING STRONGER
FRONTOGENESIS TO OUR NORTH...AND THE GFS/EC WRAPPING PCPN FURTHER
SOUTH AS MID LEVEL BAROCLINICITY DOES LIKEWISE. TOUGH FORECAST
HERE. BELIEVE ENERGY MOVING FROM SOUTHEAST OR INTO SOUTHERN ID IS
DYNAMIC AND FAR ENOUGH SOUTH TO ALLOW FOR A SOUTHERN PUSH OF
FORCING TO AN EXTENT GREATER THAN THE NAM/RAP...BUT NOT TO THE
EXTENT OF THE GFS WHICH SEEMS MUDDLED BY CONVECTIVE FEEDBACK.
INSTABILITY IS ANOTHER IMPORTANT FACTOR AS AIRMASS WILL BE FAIRLY
UNSTABLE THROUGH THE NIGHT...AGAIN SEE CONVECTIVE ACTIVITY
UPSTREAM NOW. SO...HAVE ISSUED WINTER WX ADVISORIES ACROSS OUR
NORTH FROM WHEATLAND TO FALLON COUNTIES...NORTH OF BILLINGS BUT
INCLUDING HIGHWAY 12 AND A PORTION OF I-94. GUSTY NORTH WINDS WITH
THE COLD ADVECTION WILL PRODUCE BLOWING SNOW ALONG WITH THE
ACCUMULATION...WHICH SHOULD GENERALLY RANGE FROM 1 TO 3 INCHES...
WITH MORE NORTH OF OUR CWA.
AS FOR THE CITY OF BILLINGS...MAYBE A LITTLE ACCUMULATION AFTER
MIDNIGHT BUT FEEL BRUNT OF PCPN WILL REMAIN NORTH...THOUGH WILL
SEE SCATTERED PREFRONTAL RAIN SHOWERS THIS EVENING. EXPECT UPSLOPE
SNOW SHOWERS WITH LESS THAN AN INCH ON MONDAY IN THE METRO AREA.
AS A SIDE NOTE...IF MID LEVELS STAY DRY FROM BILLINGS SOUTH
TONIGHT...COULD BE SOME LIGHT FREEZING DRIZZLE ONCE TEMPS FALL
BELOW FREEZING AS LOW LEVELS MOISTEN WITH UPSLOPE NE WINDS
DEVELOPING. WILL NEED TO KEEP WATCH OF THIS.
PHASE TWO WILL BE INFLUENCED BY THE EVOLUTION OF PHASE ONE. THIS
WILL INVOLVE DEEP CENTRAL ROCKIES CLOSED LOW AS WE WILL BE NEAR
ITS NORTHERN EXTENT. A SOUTHERN PUSH OF FRONTOGENESIS TONIGHT
WOULD LIKELY RESULT IN A MORE SOUTHERN TRACK OF THE UPPER
LOW...WITH OUR AREA MORE INFLUENCED BY WEAKER/DRY NORTHERN TROF
CURRENTLY IN SOUTHERN CANADA. IF STRONGER FORCING STAYS NORTH
TONIGHT THAN WE COULD EXPECT A MORE NORTHWARD TRACK OF THE UPPER
LOW...AND STRONGER DIFFLUENCE OVER US...AND BETTER SNOW POTENTIAL
FOR OUR SOUTHERN UPSLOPE AREAS AND SOUTHEAST MT...AS THE ECMWF HAS
BEEN CONSISTENT IN SUGGESTING. LATEST GFS KEEPS THE LOW ENTIRELY
TO OUR SOUTH...SO PLENTY OF UNCERTAINTY HERE AS WELL. WILL KEEP A
MIDDLE GROUND...WITH LIKELY POPS AND SOME ACCUMULATION ACROSS OUR
SOUTH MONDAY NIGHT AND TUESDAY. WITH A MORE NORTHERN TRACK...DEEP
DENDRITIC LAYER AND UPSLOPE FLOW COULD BRING A SIGNIFICANT SNOW
EVENT TO SUCH PLACES AS SHERIDAN...BROADUS AND ALZADA...WITH PCPN
LASTING INTO TUESDAY NIGHT. OR WITH THE SOUTHERN TRACK THESE
AREAS WOULD RECEIVE VERY LITTLE PCPN WITH AN END BY TUESDAY.
PLEASE MONITOR THE FORECAST OVER THE NEXT DAY AS ADJUSTMENTS WILL
LIKELY BE NEEDED.
AS FOR THE CITY OF BILLINGS...IT DOES NOT LOOK AS IF WE WILL
RECEIVE MUCH SNOWFALL WITH PHASE TWO EITHER...AND POSSIBLY NONE.
AGAIN THIS WILL DEPEND ON EXACT TRACK OF THE UPPER LOW.
CANADIAN AIRMASS IS QUITE COLD AND TEMPS WILL BE WELL BELOW NORMAL
THE NEXT TWO DAYS. HAVE DROPPED EXPECTED TEMPS A BIT MORE. RECORD
LOWS COULD BE CHALLENGED AT BILLINGS AND MILES CITY MONDAY NIGHT.
JKL
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
CONSENSUS OF THE EXTENDED IS FOR SLIGHTLY BELOW SEASONAL AVERAGES
FOR TEMPERATURES AND AN UNSETTLED NATURE FOR POPS. THE ONLY REAL
DRY DAY APPEARS TO BE WEDNESDAY AS A SHORT LIVED MESO RIDGE MOVES
IN. A DEEP UPPER TROUGH OVER THE GULF OF ALASKA AND THE NORTHERN
TERRITORIES DROPS SOUTHWARD TOWARD THE PACIFIC NORTHWEST THIS
WEEKEND. THIS PROCESS WILL CAUSE FALLING HEIGHTS FOR A RELATIVELY
UNSTABLE ATMOSPHERE WITH MOISTURE AND SHORTWAVES SHOOTING ACROSS
THE FORECAST AREA. IMPOSSIBLE AT THIS POINT TO PIN POINT THE BEST
DAY FOR POP CHANCES AS EXACT PLACEMENT OF APPROACHING WAVES WILL
BE CRITICAL FOR ASCENT. A BROAD BRUSHED SLIGHT CHANCE TO CHANCE
POPS SEEMS THE BEST WAY TO GO. THE WARMEST DAY SHOULD BE WEDNESDAY
WITH LESS CLOUD COVER ALLOWING A HIGH SUN ANGLE TO WORK. TWH
&&
.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO PUSH ACROSS THE
REGION. SMALL HAIL...AND LOCALLY HEAVY RAIN HAS BEEN REPORTED WITH
THESE STORMS. A STRONG COLD FRONT HAS PUSHED THROUGH KBIL...AND
KLVM...AND WILL PUSH INTO SOUTHERN TERMINALS OVERNIGHT. THIS
FRONT WILL SWITCH WINDS TO THE NORTH WITH POSSIBLE GUSTS TO 30KTS.
SNOW IS BEING REPORTED IN JUDITH GAP BEHIND THIS FRONT...AND
SHOULD REMAIN MAINLY NORTH OF A KLVM TO KBIL TO KBHK LINE. CIGS
ARE EXPECTED TO LOWER TO MVFR/IFR WITH PRECIP ACROSS THE
NORTH...WITH LOW CLOUDS SPREADING SOUTH OVERNIGHT. LIGHT
SNOW...AND POSSIBLY LIGHT FREEZING DRIZZLE...WILL ACCOMPANY THE
LOWERING CEILINGS. LOW CLOUDS...SNOW AND GUSTY NORTH WINDS WILL
CONTINUE THROUGH MONDAY MORNING. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 028/034 018/036 022/048 033/056 033/053 032/053 029/052
87/S 31/B 01/B 33/W 22/W 33/W 33/W
LVM 028/039 018/038 022/048 032/053 029/051 029/050 026/049
66/S 41/B 01/B 32/W 22/W 33/W 33/W
HDN 030/035 019/035 019/047 029/057 028/054 027/054 026/054
87/S 41/B 11/B 33/W 22/W 33/W 33/W
MLS 030/032 016/033 018/044 027/052 027/052 028/052 025/052
88/S 21/B 11/B 23/W 22/W 33/W 32/W
4BQ 033/036 017/031 016/041 024/052 024/051 026/051 024/051
57/S 63/S 21/B 23/W 22/W 33/W 33/W
BHK 030/031 015/029 015/038 022/045 027/046 026/046 021/046
88/S 42/S 11/B 23/W 22/W 23/W 32/W
SHR 032/037 020/031 015/043 026/054 027/051 027/052 024/051
28/S 75/S 21/B 23/W 22/W 23/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MDT MONDAY FOR
ZONES 28-29-42-63.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MDT MONDAY FOR
ZONES 31>33.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS OMAHA/VALLEY NE
132 PM CDT SAT APR 6 2013
.UPDATE...
&
.AVIATION...18Z TAFS FOR KOFK...KOMA AND KLNK.
MAIN AVIATION CONCERN FOR NOW IS GUSTY NORTHWEST WINDS 20-30KT
OVER ERN NEB THIS AFTN BEHIND A SURFACE COLD FRONT PUSHING SWD
THRU THE CNTRL PLAINS. EXPECT THOUGH WIND WILL RELAX BY EARLY
EVENING AND BECOME LIGHT AND VARIABLE THRU TONIGHT. OTHERWISE VFR
CONDITIONS WILL PREVAIL THRU THE 24HR FCST PD.
DEE
PREV DISCUSSION... /ISSUED 326 AM CDT SAT APR 6 2013/
DISCUSSION...
WEAK WAVE MOVING OFF THE HIGH PLAINS WILL PUSH A FRONT INTO THE
AREA THIS MORNING...WHICH CURRENTLY EXTENDED FROM KMCK TO KANW AT
08Z. THERE DOES APPEAR TO BE SOME THICKER CLOUDS 6-9000 FEET
BEHIND THE FRONT...WITH LATEST RAP MODEL RUNS SUGGESTING THAT AT
LEAST A FEW SPRINKLES COULD MOVE INTO NORTHEAST NEBRASKA THROUGH
THE MORNING...BUT VERY DOUBTFUL THAT IT WOULD BE ENOUGH TO MEASURE.
ALSO GIVEN TRAJECTORY OF EXISTING SHOWERS IN SOUTHWEST...VERY
DOUBTFUL IT WOULD EXTEND TO ANYWHERE SOUTH OF THE PLATTE RIVER.
OTHERWISE...WINDS BECOME WEST TO NORTHWEST THROUGH THE DAY WITH
BREEZY CONDITIONS AND WARM TEMPERATURES IN THE MID 60S TO LOWER 70S.
ANOTHER VERY SUBTLE WAVE MOVES OUT OF THE NORTHERN ROCKIES TONIGHT
WITH A VERY WEAK REINFORCING FRONTAL BOUNDARY. HAVE DOUBTS THAT
ANY PRECIP WOULD BE GENERATED AND WILL JUST HIT THE CLOUDS A
LITTLE HARDER OVERNIGHT.
THE NEXT WAVE OF INTEREST...WHICH IS CURRENTLY STILL OF THE
PACIFIC NORTHWEST COAST...MOVES INTO THE REGION SUNDAY AFTERNOON
AND NIGHT...BRINGING A FAIRLY DECENT CHANCE FOR RAIN...THUS HAVE
INCREASING CHANCES...EVENTUALLY REACHING 50 TO 70 PERCENT AS THE
WAVE MOVES THROUGH. INSTABILITY WILL ALSO BE INCREASING...THUS
HAVE THUNDER MENTIONED...LOOKS LIKE HEAVIEST PRECIP WITH THIS
ROUND WOULD SOUTH OF I80.
THERE WILL LIKELY BE A BREAK IN ANY PRECIP BY VERY LATE SUNDAY
NIGHT THROUGH MONDAY MORNING...BUT YET ANOTHER ROUND OF PRECIP IS
EXPECTED TO DEVELOP MONDAY NIGHT AND LINGER THROUGH MIDWEEK AS A
FAIRLY STRONG CLOSED LOW TROUGH DEVELOPS IN THE FOUR CORNERS
REGION. THIS WILL INITIALLY START AS SHOWERS AND THUNDERSTORMS...
ALTHOUGH IT SEEMS THAT THE BEST SEVERE THREAT IS SETTING UP JUST
SOUTH OF THE REGION ALONG/SOUTH OF THE KS/NE BORDER REGION. OUR
AREA APPEARS TO REMAIN ON THE COOLER SIDE OF THE BOUNDARY...WHICH
ALSO BRINGS IN A PRECIP TYPE ISSUE IN NORTHEAST NEBRASKA BY
TUESDAY NIGHT AND WEDNESDAY WHERE THE RAIN COULD MIX WITH SNOW.
THERE AREA STILL A FEW MODEL DISCREPANCIES THAT FAR OUT...ALL OF
WHICH WILL HAVE PRETTY BIG IMPACTS ON THE REGION...EITHER THE
POTENTIAL FOR MORE SNOW IN NORTHEAST NEBRASKA...OR THE INCREASED
POTENTIAL FOR A LITTLE MORE SEVERE THREAT A LITTLE FURTHER NORTH
INTO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...ALL OF WHICH WON`T BE
SOLVED UNTIL WE GET CLOSER TO THAT TIME FRAME. PRECIP COULD LINGER
THROUGH THURSDAY...BUT AGAIN THAT`S HIGHLY DEPENDENT ON LATER
MODEL SOLUTIONS.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1215 PM CDT SAT APR 6 2013
.UPDATE...
ISSUED AT 649 AM CDT SAT APR 6 2013
A COLD FRONT IS PROGRESSING THRU THE FCST AREA ATTM. EXPECT AN
ABRUPT WIND SHIFT TO NW AND A 1-2 HR BURST OF 15-25G30 MPH. ORD
GUSTED TO 36 MPH AT 423 AM. WE/RE ALSO SEEING A SUBSTANTIAL DROP
IN DWPTS. SO USED HRRR TO BETTER DEPICT DWPT TRENDS. ALSO
SHARPENED THE CLEARING LINE IN SKY COVER AS THE BACK EDGE OF THE
CLOUDS ARE MOVING E AT 33 KTS. CLOUDS WILL CLEAR FROM W TO E AND
SHOULD BE E OF THE FCST AREA BY 18Z.
FOR WHAT IT/S WORTH...A MINOR HEAT BURST OCCURRED AT MCK AROUND
149 AM. THE TEMP INCREASED FROM 60 TO 65 WITH A G49 KTS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT SAT APR 6 2013
ONE CONCERN THIS MORNING WILL BE THE SLIGHT POSSIBILITY OF A HEAT
BURST. FORECAST SOUNDINGS INDICATE A VERY DRY LOWER ATMOSPHERE
BELOW 600 MB...WITH HIGH BASED SHOWERS ABOVE 600 MB. MCCOOK SAW A
HEAT BURST JUST BEFORE 2 AM THIS MORNING AS A DIEING SHOWER MOVED
OVER THE CITY THAT RESULTED IN A SEVERAL DEGREE BUMP IN SFC
TEMPERATURE AND A SUBSEQUENT WIND GUST TO 56 MPH. AREA RADARS
CONTINUE TO SHOW HIGH BASED SHOWERS ACROSS THE FORECAST AREA THAT
ARE LIKELY EVAPORATING PRIOR TO REACHING THE GROUND. THERE COULD
BE A SPRINKLE OR TWO...BUT MOST PRECIPITATION WILL BE VIRGA AND
EVAPORATE. AGAIN...WILL NEED TO WATCH OUT FOR A FEW STRAY HEAT
BURSTS THROUGH MID MORNING.
A WEAK SHORTWAVE AND SUBSEQUENT SFC TROUGH ARE TRACKING ACROSS
OUR FORECAST AREA THIS MORNING AND EXPECT SUBSIDENCE AND CLEARING
SKIES BEHIND THE SYSTEM THIS AFTERNOON. THERE WILL BE GOOD MIXING
THIS AFTERNOON WITH MORE SUNSHINE AND UNIDIRECTIONAL WINDS IN THE
VERTICAL PROFILE. THIS SHOULD HELP US TO WARM BACK INTO THE LOWER
70S...BUT WILL ALSO ALLOW FOR STRONGER WINDS TO MIX DOWN TO THE
SFC. IT SHOULD NOT BE AS WINDY AS YESTERDAY...BUT STILL EXPECT AT
LEAST A RATHER BREEZY DAY. IN ADDITION...DEWPOINT AND RH VALUES
WILL LIKELY FALL SOME DURING PEAK MIXING AROUND MID AFTERNOON
RESULTING IN AN ELEVATED FIRE DANGER ACROSS OUR FAR
WEST...PRIMARILY WEST OF HIGHWAY 183. WE USED A MIX DOWN SMART
TOOL TO DERIVE OUR DEWPOINT VALUES FOR THIS AFTERNOON AND BUMPED
OUR WIND SPEEDS UP A FEW KNOTS DUE TO THE EXPECTED MIXING. AM NOT
EXPECTING A NEED FOR FIRE WEATHER HEADLINES AT THIS TIME...BUT IT
IS SOMETHING WORTH KEEPING AN EYE ON.
TONIGHT...THE WIND WILL QUICKLY DIE OFF THIS EVENING AFTER SUNSET
DUE TO THE LOSS OF HEATING/MIXING. CLOUDS WILL BE ON THE INCREASE
TONIGHT AS OUR NEXT STORM SYSTEM FINALLY COMES ASHORE ACROSS THE
PACIFIC NORTHWEST AND A LEAD SHORT WAVE TRACKS OUT OF THE ROCKIES
AND INTO THE HIGH PLAINS. EXPECT PRECIPITATION OVERNIGHT WILL BE
CONFINED TO THE HIGH PLAINS WITH DRY WEATHER FOR OUR FORECAST
AREA.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 405 AM CDT SAT APR 6 2013
MAIN STORY: UNSETTLED PATTERN TO DEVELOP WITH INCREASING TEMP
GRADIENT SETTING UP A BATTLE GROUND OVER THE CNTRL PLAINS AS THE NAO
FADES ALLOWING FOR UPPER-LVL RIDGE TO BUILD OVER THE SE USA.
PATTERN: THE CURRENT PNA/NAO PATTERNS WILL REVERSE OVER THE NEXT 10
DAYS. THE -NAO WILL BECOME A NON-PLAYER AS IT HEADS TO ROUGHLY
NEUTRAL WHILE THE PNA TURNS STRONGLY NEGATIVE. WITH THE PNA
MAGNITUDE BECOMING DOMINANT...EXPECT A LONG-WAVE /LGWV/ TROF TO
DEVELOP OVER THE WRN USA WITH A RIDGE OVER THE E. THIS WILL SETUP AN
INTENSE TEMP GRADIENT AS SUMMER-LIKE WARMTH DEVELOPS OVER THE E...
AND THE WRN TROF WILL ALLOW CANADIAN COLD TO HEAD S. SO WHILE PARTS
OF THE FCST AREA WILL ENJOY BRIEF BUT POTENTIALLY SIGNIFICANT
WARM-UPS...IT APPEARS THAT THE PATTERN FAVORS TEMPS AVERAGING COOLER
THAN NORMAL AND THIS IS IN AGREEMENT WITH YESTERDAY/S ASSESSMENT
FROM THE CPC 6-10 AND 8-14 DAY OUTLOOKS. THIS ALSO SUGGESTS MORE
ACTIVE WX IS ON THE WAY.
EXPLOSIVE CYCLOGENESIS IS UNDERWAY OFF THE E COAST OF ASIA PER
SATELLITE. THIS WILL CAUSE DOWNSTREAM EXCITATION OF THE LGWV
FLOW...SENDING THE STALLED UPPER LOW /CURRENTLY S OF THE ALEUTIANS/
ONSHORE IN THE PAC NW SUN AND INTO THE DESERT SW MON-TUE. THIS WILL
CARVE OUT A LGWV TROF OVER THE WRN USA. THIS WILL INDUCE CO LEE
CYCLOGENESIS THAT COULD RESULT IN MULTIPLE HAZARDS EARLY NEXT WEEK.
UPPER-LEVELS: AS TODAY/S LOW PRES DEPARTS FOR THE GREAT LAKES...ITS
TRAILING COOL FRONT WILL SLIP INTO THE FCST AREA SUN AND BECOME
QUASI-STATIONARY NEAR THE NEB-KS BORDER INTO EARLY NEXT WEEK. A
COUPLE OF WEAK PV ANOMALIES WILL MOVE THRU THE CNTRL PLAINS SUN-SUN
NGT AS A COUPLED JET STRUCTURE DEVELOPS. THE MAIN PV ANOMALY AND 150
KT JET CORE MOVE ONSHORE DURING THAT TIME FRAME AND INITIATE LEE
CYCLOGENESIS MON. THIS LOW THEN HEADS E INTO THE OH VALLEY WED-THU.
FCST CONFIDENCE: THE OVERALL EVOLUTION OF THE LGWV PATTERN REMAINS
HIGH...BUT CONFIDENCE CONTS LOW DUE TO MODEL SPREAD ON THE TIMING/
LOCATION/INTENSITY DETAILS.
MODELS: PREDICTABLY THE GFS RUNS ARE ON THE FASTER END OF THE
GUIDANCE ENVELOPE WHILE THE EC RUNS ARE ON THE SLOWER END. THIS IS
ESPECIALLY APPARENT OVERLAYING THE MODELS TOGETHER AT 00Z/WED...WHEN
THE 18Z/00Z GFS HAS ITS H5 LOWS OVER THE CNTRL PLAINS AND THE EC IS
BACK OVER THE 4-CORNERS OR WRN CO. THE 00Z GEM IS A BLEND OF THE TWO
WITH A LEAD LOW EJECTING WITH THE GFS BUT HANGS BACK A TROF OVER THE
SW. DUE TO MODEL UNCERTAINTY PREFER TO FOLLOW WPC FCST WHICH IS
BASED ON THE EC ENSEMBLE MEAN.
HAZARDS: MULTIPLE TSTM CHANCES THAT COULD CLIMAX IN SVR TSTMS TUE...
PRIMARILY OVER N-CNTRL KS. MEASURABLE SNOW IS POSSIBLE FOR PARTS OF
THE FCST AREA TUE-WED.
THE DAILY DETAILS...
SUN: INSTABILITY BURST WITH A PERIOD OF SHWRS WITH EMBEDDED THUNDER.
TEMPS ARE DEPENDENT ON CLOUDS/PCPN. CONFIDENCE IS LOW. USED
CONSENSUS OF 2M TEMPS AND PREVIOUS FCST WITH NO BIAS CORRECTION.
POPS ARE A BLEND OF THE 21Z SREF AND THE 18Z/00Z NAM.
SUN NGT: PROBABLY A BREAK WITH A SHRTWV RIDGE.
EXACT EVOLUTION IS STILL SHAKY MON-TUE BUT IT APPEARS WE CAN NARROW
THE MAIN SHOW TO THE MON NGT-TUE-TUE NGT TIME FRAME. THIS HAS
POTENTIAL TO BE A LONG-DURATION EVENT THAT COULD BRING MULTIPLE
WAVES OF SOAKING RAIN.
MON: A WARM FRONT DEVELOPS NEAR I-70 WITH THE NRN STREAM DELIVERING
A STRONG COLD FRONT FROM THE N. EXPECT TSTMS TO ERUPT ALONG THE WARM
FRONT IN THE AFTN-EVNG. BEFORE THE MODEL CONVECTIVE SCHEMES TRIGGER
THE SHEAR/INSTABILITY IS STRONG ENUF FOR ELEVATED SVR OVER OUR
N-CNTRL KS COUNTIES.
MON NGT-TUE: THE FRONT MERGE CREATING AN INTENSE TEMP GRADIENT.
STRONG ASCENT UP THE COMBINED FRONTAL ZONE WILL WILL CONT TO TRIGGER
WAVES OF SHWRS/TSTMS. THE COLD AIR SHOULD BECOME DEEP ENUF TO END
THE THUNDER TUE FROM THE TRI-CITIES N AND W.
TEMPS: WOULD NOT BE SURPRISED TO SEE ODX/LXN IN THE 30S AT 4 PM TUE
AND K75/K61 IN THE 70S...OR 40S/NEAR 80.
SEVERE: MAIN CONCERN TUE AFTN/EVNG...DOES THIS TIME FRAME COINCIDE
WITH SFC-BASED TSTM DEVELOPMENT? IT/S POSSIBLE THE WARM SECTOR GETS
SHUNTED S/SE OF THE FCST AREA. REGARDLESS...ELEVATED SVR TSTMS
REMAIN A POSSIBILITY BUT THAT WOULD LIMIT THE THREAT TO
PREDOMINANTLY SEVERE HAIL.
TUE NGT: THE R/S LINE MOVES IN BUT PCPN SHOULD BE LIGHT. MODELS ARE
IN GOOD AGREEMENT THAT THE H7 LOW TRACKS ACROSS THE FCST AREA. THIS
MEANS DRY SLOT HERE...BUT A MAJOR SNOWSTORM WILL NOT BE FAR AWAY
OVER WRN/NRN NEB.
WED: IF THE SLOWER EC EVOLUTION VERIFIES...THEN A TOUCH OF LIGHT R/S
MAY LINGER. OTHERWISE...BLUSTERY AND COLD FOR THIS TIME OF YEAR. H8
TEMPS ARE FCST TO NEAR -2 STANDARD DEVIATIONS. FULL SUN AND NO
DOWNSLOPE WOULD ONLY RESULT IN HIGHS ROUGHLY 39-45F. FOR WHAT IT/S
WORTH THE 00Z EC/GEM/GFS/DGEX HIGHS ARE FCST IN THE UPR 20S AND 30S
FOR MOST OF THE FCST AREA.
ANALOGS: HIGH TEMPS IN THE 30S ARE NOT OUT OF THE QUESTION. THE
COOPERATIVE INSTITUTE FOR PCPN SYSTEMS /CIPS/ TOP ANALOGS INCLUDE
APR 13-14 1983. HIGH TEMPS WERE 34 AND 39F WITH 2" OF SNOW. APR 5-6
2001 WERE SIMILAR.
THU-FRI: HIGH PRES. QUIET AND DRY WITH BELOW NORMAL TEMPS IN THE
WAKE OF THE DEPARTING STORM. WE ARE MAINTAINING A LOW POP THU BUT
THIS IS MAINLY DUE TO UNCERTAINTY IN HOW LONG THE UPPER-LVL SYSTEM
HANGS AROUND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1215 PM CDT SAT APR 6 2013
A COLD FRONT MOVED THROUGH THE KGRI TERMINAL AREA THIS MORNING AND
WINDS BEHIND THE FRONT ARE GUSTY FROM THE NORTHWEST. THIS SHOULD
CONTINUE THROUGH THE DAY LIGHT HOURS BEFORE THE WINDS BECOME LIGHT
AND VARIABLE DURING THE NIGHT. A BAND OF LOW TO MID LEVEL CLOUDS
WILL MOVE THROUGH THE AREA EARLY THIS AFTERNOON...BUT SHOULD BE
OUT BEFORE TOO LONG. THE CEILINGS HAVE RISEN ABOVE MVFR VALUES AND
SHOULD REMAIN SO. MOVE MID LEVEL CLOUDS WILL MOVE INTO THE AREA
THIS EVENING AND CONTINUE THROUGH SUNDAY MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
649 AM CDT SAT APR 6 2013
.UPDATE...
ISSUED AT 649 AM CDT SAT APR 6 2013
A COLD FRONT IS PROGRESSING THRU THE FCST AREA ATTM. EXPECT AN
ABRUPT WIND SHIFT TO NW AND A 1-2 HR BURST OF 15-25G30 MPH. ORD
GUSTED TO 36 MPH AT 423 AM. WE/RE ALSO SEEING A SUBSTANTIAL DROP
IN DWPTS. SO USED HRRR TO BETTER DEPICT DWPT TRENDS. ALSO
SHARPENED THE CLEARING LINE IN SKY COVER AS THE BACK EDGE OF THE
CLOUDS ARE MOVING E AT 33 KTS. CLOUDS WILL CLEAR FROM W TO E AND
SHOULD BE E OF THE FCST AREA BY 18Z.
FOR WHAT IT/S WORTH...A MINOR HEAT BURST OCCURRED AT MCK AROUND
149 AM. THE TEMP INCREASED FROM 60 TO 65 WITH A G49 KTS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT SAT APR 6 2013
ONE CONCERN THIS MORNING WILL BE THE SLIGHT POSSIBILITY OF A HEAT
BURST. FORECAST SOUNDINGS INDICATE A VERY DRY LOWER ATMOSPHERE
BELOW 600 MB...WITH HIGH BASED SHOWERS ABOVE 600 MB. MCCOOK SAW A
HEAT BURST JUST BEFORE 2 AM THIS MORNING AS A DIEING SHOWER MOVED
OVER THE CITY THAT RESULTED IN A SEVERAL DEGREE BUMP IN SFC
TEMPERATURE AND A SUBSEQUENT WIND GUST TO 56 MPH. AREA RADARS
CONTINUE TO SHOW HIGH BASED SHOWERS ACROSS THE FORECAST AREA THAT
ARE LIKELY EVAPORATING PRIOR TO REACHING THE GROUND. THERE COULD
BE A SPRINKLE OR TWO...BUT MOST PRECIPITATION WILL BE VIRGA AND
EVAPORATE. AGAIN...WILL NEED TO WATCH OUT FOR A FEW STRAY HEAT
BURSTS THROUGH MID MORNING.
A WEAK SHORTWAVE AND SUBSEQUENT SFC TROUGH ARE TRACKING ACROSS
OUR FORECAST AREA THIS MORNING AND EXPECT SUBSIDENCE AND CLEARING
SKIES BEHIND THE SYSTEM THIS AFTERNOON. THERE WILL BE GOOD MIXING
THIS AFTERNOON WITH MORE SUNSHINE AND UNIDIRECTIONAL WINDS IN THE
VERTICAL PROFILE. THIS SHOULD HELP US TO WARM BACK INTO THE LOWER
70S...BUT WILL ALSO ALLOW FOR STRONGER WINDS TO MIX DOWN TO THE
SFC. IT SHOULD NOT BE AS WINDY AS YESTERDAY...BUT STILL EXPECT AT
LEAST A RATHER BREEZY DAY. IN ADDITION...DEWPOINT AND RH VALUES
WILL LIKELY FALL SOME DURING PEAK MIXING AROUND MID AFTERNOON
RESULTING IN AN ELEVATED FIRE DANGER ACROSS OUR FAR
WEST...PRIMARILY WEST OF HIGHWAY 183. WE USED A MIX DOWN SMART
TOOL TO DERIVE OUR DEWPOINT VALUES FOR THIS AFTERNOON AND BUMPED
OUR WIND SPEEDS UP A FEW KNOTS DUE TO THE EXPECTED MIXING. AM NOT
EXPECTING A NEED FOR FIRE WEATHER HEADLINES AT THIS TIME...BUT IT
IS SOMETHING WORTH KEEPING AN EYE ON.
TONIGHT...THE WIND WILL QUICKLY DIE OFF THIS EVENING AFTER SUNSET
DUE TO THE LOSS OF HEATING/MIXING. CLOUDS WILL BE ON THE INCREASE
TONIGHT AS OUR NEXT STORM SYSTEM FINALLY COMES ASHORE ACROSS THE
PACIFIC NORTHWEST AND A LEAD SHORT WAVE TRACKS OUT OF THE ROCKIES
AND INTO THE HIGH PLAINS. EXPECT PRECIPITATION OVERNIGHT WILL BE
CONFINED TO THE HIGH PLAINS WITH DRY WEATHER FOR OUR FORECAST
AREA.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 405 AM CDT SAT APR 6 2013
MAIN STORY: UNSETTLED PATTERN TO DEVELOP WITH INCREASING TEMP
GRADIENT SETTING UP A BATTLE GROUND OVER THE CNTRL PLAINS AS THE NAO
FADES ALLOWING FOR UPPER-LVL RIDGE TO BUILD OVER THE SE USA.
PATTERN: THE CURRENT PNA/NAO PATTERNS WILL REVERSE OVER THE NEXT 10
DAYS. THE -NAO WILL BECOME A NON-PLAYER AS IT HEADS TO ROUGHLY
NEUTRAL WHILE THE PNA TURNS STRONGLY NEGATIVE. WITH THE PNA
MAGNITUDE BECOMING DOMINANT...EXPECT A LONG-WAVE /LGWV/ TROF TO
DEVELOP OVER THE WRN USA WITH A RIDGE OVER THE E. THIS WILL SETUP AN
INTENSE TEMP GRADIENT AS SUMMER-LIKE WARMTH DEVELOPS OVER THE E...
AND THE WRN TROF WILL ALLOW CANADIAN COLD TO HEAD S. SO WHILE PARTS
OF THE FCST AREA WILL ENJOY BRIEF BUT POTENTIALLY SIGNIFICANT
WARM-UPS...IT APPEARS THAT THE PATTERN FAVORS TEMPS AVERAGING COOLER
THAN NORMAL AND THIS IS IN AGREEMENT WITH YESTERDAY/S ASSESSMENT
FROM THE CPC 6-10 AND 8-14 DAY OUTLOOKS. THIS ALSO SUGGESTS MORE
ACTIVE WX IS ON THE WAY.
EXPLOSIVE CYCLOGENESIS IS UNDERWAY OFF THE E COAST OF ASIA PER
SATELLITE. THIS WILL CAUSE DOWNSTREAM EXCITATION OF THE LGWV
FLOW...SENDING THE STALLED UPPER LOW /CURRENTLY S OF THE ALEUTIANS/
ONSHORE IN THE PAC NW SUN AND INTO THE DESERT SW MON-TUE. THIS WILL
CARVE OUT A LGWV TROF OVER THE WRN USA. THIS WILL INDUCE CO LEE
CYCLOGENESIS THAT COULD RESULT IN MULTIPLE HAZARDS EARLY NEXT WEEK.
UPPER-LEVELS: AS TODAY/S LOW PRES DEPARTS FOR THE GREAT LAKES...ITS
TRAILING COOL FRONT WILL SLIP INTO THE FCST AREA SUN AND BECOME
QUASI-STATIONARY NEAR THE NEB-KS BORDER INTO EARLY NEXT WEEK. A
COUPLE OF WEAK PV ANOMALIES WILL MOVE THRU THE CNTRL PLAINS SUN-SUN
NGT AS A COUPLED JET STRUCTURE DEVELOPS. THE MAIN PV ANOMALY AND 150
KT JET CORE MOVE ONSHORE DURING THAT TIME FRAME AND INITIATE LEE
CYCLOGENESIS MON. THIS LOW THEN HEADS E INTO THE OH VALLEY WED-THU.
FCST CONFIDENCE: THE OVERALL EVOLUTION OF THE LGWV PATTERN REMAINS
HIGH...BUT CONFIDENCE CONTS LOW DUE TO MODEL SPREAD ON THE TIMING/
LOCATION/INTENSITY DETAILS.
MODELS: PREDICTABLY THE GFS RUNS ARE ON THE FASTER END OF THE
GUIDANCE ENVELOPE WHILE THE EC RUNS ARE ON THE SLOWER END. THIS IS
ESPECIALLY APPARENT OVERLAYING THE MODELS TOGETHER AT 00Z/WED...WHEN
THE 18Z/00Z GFS HAS ITS H5 LOWS OVER THE CNTRL PLAINS AND THE EC IS
BACK OVER THE 4-CORNERS OR WRN CO. THE 00Z GEM IS A BLEND OF THE TWO
WITH A LEAD LOW EJECTING WITH THE GFS BUT HANGS BACK A TROF OVER THE
SW. DUE TO MODEL UNCERTAINTY PREFER TO FOLLOW WPC FCST WHICH IS
BASED ON THE EC ENSEMBLE MEAN.
HAZARDS: MULTIPLE TSTM CHANCES THAT COULD CLIMAX IN SVR TSTMS TUE...
PRIMARILY OVER N-CNTRL KS. MEASURABLE SNOW IS POSSIBLE FOR PARTS OF
THE FCST AREA TUE-WED.
THE DAILY DETAILS...
SUN: INSTABILITY BURST WITH A PERIOD OF SHWRS WITH EMBEDDED THUNDER.
TEMPS ARE DEPENDENT ON CLOUDS/PCPN. CONFIDENCE IS LOW. USED
CONSENSUS OF 2M TEMPS AND PREVIOUS FCST WITH NO BIAS CORRECTION.
POPS ARE A BLEND OF THE 21Z SREF AND THE 18Z/00Z NAM.
SUN NGT: PROBABLY A BREAK WITH A SHRTWV RIDGE.
EXACT EVOLUTION IS STILL SHAKY MON-TUE BUT IT APPEARS WE CAN NARROW
THE MAIN SHOW TO THE MON NGT-TUE-TUE NGT TIME FRAME. THIS HAS
POTENTIAL TO BE A LONG-DURATION EVENT THAT COULD BRING MULTIPLE
WAVES OF SOAKING RAIN.
MON: A WARM FRONT DEVELOPS NEAR I-70 WITH THE NRN STREAM DELIVERING
A STRONG COLD FRONT FROM THE N. EXPECT TSTMS TO ERUPT ALONG THE WARM
FRONT IN THE AFTN-EVNG. BEFORE THE MODEL CONVECTIVE SCHEMES TRIGGER
THE SHEAR/INSTABILITY IS STRONG ENUF FOR ELEVATED SVR OVER OUR
N-CNTRL KS COUNTIES.
MON NGT-TUE: THE FRONT MERGE CREATING AN INTENSE TEMP GRADIENT.
STRONG ASCENT UP THE COMBINED FRONTAL ZONE WILL WILL CONT TO TRIGGER
WAVES OF SHWRS/TSTMS. THE COLD AIR SHOULD BECOME DEEP ENUF TO END
THE THUNDER TUE FROM THE TRI-CITIES N AND W.
TEMPS: WOULD NOT BE SURPRISED TO SEE ODX/LXN IN THE 30S AT 4 PM TUE
AND K75/K61 IN THE 70S...OR 40S/NEAR 80.
SEVERE: MAIN CONCERN TUE AFTN/EVNG...DOES THIS TIME FRAME COINCIDE
WITH SFC-BASED TSTM DEVELOPMENT? IT/S POSSIBLE THE WARM SECTOR GETS
SHUNTED S/SE OF THE FCST AREA. REGARDLESS...ELEVATED SVR TSTMS
REMAIN A POSSIBILITY BUT THAT WOULD LIMIT THE THREAT TO
PREDOMINANTLY SEVERE HAIL.
TUE NGT: THE R/S LINE MOVES IN BUT PCPN SHOULD BE LIGHT. MODELS ARE
IN GOOD AGREEMENT THAT THE H7 LOW TRACKS ACROSS THE FCST AREA. THIS
MEANS DRY SLOT HERE...BUT A MAJOR SNOWSTORM WILL NOT BE FAR AWAY
OVER WRN/NRN NEB.
WED: IF THE SLOWER EC EVOLUTION VERIFIES...THEN A TOUCH OF LIGHT R/S
MAY LINGER. OTHERWISE...BLUSTERY AND COLD FOR THIS TIME OF YEAR. H8
TEMPS ARE FCST TO NEAR -2 STANDARD DEVIATIONS. FULL SUN AND NO
DOWNSLOPE WOULD ONLY RESULT IN HIGHS ROUGHLY 39-45F. FOR WHAT IT/S
WORTH THE 00Z EC/GEM/GFS/DGEX HIGHS ARE FCST IN THE UPR 20S AND 30S
FOR MOST OF THE FCST AREA.
ANALOGS: HIGH TEMPS IN THE 30S ARE NOT OUT OF THE QUESTION. THE
COOPERATIVE INSTITUTE FOR PCPN SYSTEMS /CIPS/ TOP ANALOGS INCLUDE
APR 13-14 1983. HIGH TEMPS WERE 34 AND 39F WITH 2" OF SNOW. APR 5-6
2001 WERE SIMILAR.
THU-FRI: HIGH PRES. QUIET AND DRY WITH BELOW NORMAL TEMPS IN THE
WAKE OF THE DEPARTING STORM. WE ARE MAINTAINING A LOW POP THU BUT
THIS IS MAINLY DUE TO UNCERTAINTY IN HOW LONG THE UPPER-LVL SYSTEM
HANGS AROUND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 526 AM CDT SAT APR 6 2013
THE PRIMARY AVIATION CONCERN WILL CONTINUE TO CENTER AROUND THE
WIND. A TROUGH AXIS IS PASSING THROUGH THE FORECAST AREA THIS
MORNING TURNING THE WIND FROM SOUTHWEST TO NORTHWESTERLY. THE
NORTHWEST WIND MAY BE GUSTY AT TIMES TODAY...BUT SHOULD RAPIDLY
DIE DOWN AROUND SUNSET. EXPECT FEWER CLOUDS TODAY...AND MOST ALL
OF THE CLOUDS WILL BE OF THE MID TO HIGH VARIETY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
614 AM CDT SAT APR 6 2013
.AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDITIONS ARE ANTICIPATED WITH A WIND SHIFT TO THE NORTHWEST
IN THE FIRST 6 HOURS OF THE TAF CYCLE AS A COLD FRONT DROPS INTO
THE REGION. MID CLOUDS ARE FORECAST TO DRIFT OVERHEAD THROUGHOUT
MUCH OF THE DAY.
KERN
&&
.PREV DISCUSSION... /ISSUED 326 AM CDT SAT APR 6 2013/
DISCUSSION...
WEAK WAVE MOVING OFF THE HIGH PLAINS WILL PUSH A FRONT INTO THE
AREA THIS MORNING...WHICH CURRENTLY EXTENDED FROM KMCK TO KANW AT
08Z. THERE DOES APPEAR TO BE SOME THICKER CLOUDS 6-9000 FEET
BEHIND THE FRONT...WITH LATEST RAP MODEL RUNS SUGGESTING THAT AT
LEAST A FEW SPRINKLES COULD MOVE INTO NORTHEAST NEBRASKA THROUGH
THE MORNING...BUT VERY DOUBTFUL THAT IT WOULD BE ENOUGH TO MEASURE.
ALSO GIVEN TRAJECTORY OF EXISTING SHOWERS IN SOUTHWEST...VERY
DOUBTFUL IT WOULD EXTEND TO ANYWHERE SOUTH OF THE PLATTE RIVER.
OTHERWISE...WINDS BECOME WEST TO NORTHWEST THROUGH THE DAY WITH
BREEZY CONDITIONS AND WARM TEMPERATURES IN THE MID 60S TO LOWER 70S.
ANOTHER VERY SUBTLE WAVE MOVES OUT OF THE NORTHERN ROCKIES TONIGHT
WITH A VERY WEAK REINFORCING FRONTAL BOUNDARY. HAVE DOUBTS THAT
ANY PRECIP WOULD BE GENERATED AND WILL JUST HIT THE CLOUDS A
LITTLE HARDER OVERNIGHT.
THE NEXT WAVE OF INTEREST...WHICH IS CURRENTLY STILL OF THE
PACIFIC NORTHWEST COAST...MOVES INTO THE REGION SUNDAY AFTERNOON
AND NIGHT...BRINGING A FAIRLY DECENT CHANCE FOR RAIN...THUS HAVE
INCREASING CHANCES...EVENTUALLY REACHING 50 TO 70 PERCENT AS THE
WAVE MOVES THROUGH. INSTABILITY WILL ALSO BE INCREASING...THUS
HAVE THUNDER MENTIONED...LOOKS LIKE HEAVIEST PRECIP WITH THIS
ROUND WOULD SOUTH OF I80.
THERE WILL LIKELY BE A BREAK IN ANY PRECIP BY VERY LATE SUNDAY
NIGHT THROUGH MONDAY MORNING...BUT YET ANOTHER ROUND OF PRECIP IS
EXPECTED TO DEVELOP MONDAY NIGHT AND LINGER THROUGH MIDWEEK AS A
FAIRLY STRONG CLOSED LOW TROUGH DEVELOPS IN THE FOUR CORNERS
REGION. THIS WILL INITIALLY START AS SHOWERS AND THUNDERSTORMS...
ALTHOUGH IT SEEMS THAT THE BEST SEVERE THREAT IS SETTING UP JUST
SOUTH OF THE REGION ALONG/SOUTH OF THE KS/NE BORDER REGION. OUR
AREA APPEARS TO REMAIN ON THE COOLER SIDE OF THE BOUNDARY...WHICH
ALSO BRINGS IN A PRECIP TYPE ISSUE IN NORTHEAST NEBRASKA BY
TUESDAY NIGHT AND WEDNESDAY WHERE THE RAIN COULD MIX WITH SNOW.
THERE AREA STILL A FEW MODEL DISCREPANCIES THAT FAR OUT...ALL OF
WHICH WILL HAVE PRETTY BIG IMPACTS ON THE REGION...EITHER THE
POTENTIAL FOR MORE SNOW IN NORTHEAST NEBRASKA...OR THE INCREASED
POTENTIAL FOR A LITTLE MORE SEVERE THREAT A LITTLE FURTHER NORTH
INTO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...ALL OF WHICH WON`T BE
SOLVED UNTIL WE GET CLOSER TO THAT TIME FRAME. PRECIP COULD LINGER
THROUGH THURSDAY...BUT AGAIN THAT`S HIGHLY DEPENDENT ON LATER
MODEL SOLUTIONS.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
326 AM CDT SAT APR 6 2013
.DISCUSSION...
WEAK WAVE MOVING OFF THE HIGH PLAINS WILL PUSH A FRONT INTO THE
AREA THIS MORNING...WHICH CURRENTLY EXTENDED FROM KMCK TO KANW AT
08Z. THERE DOES APPEAR TO BE SOME THICKER CLOUDS 6-9000 FEET
BEHIND THE FRONT...WITH LATEST RAP MODEL RUNS SUGGESTING THAT AT
LEAST A FEW SPRINKLES COULD MOVE INTO NORTHEAST NEBRASKA THROUGH
THE MORNING...BUT VERY DOUBTFUL THAT IT WOULD BE ENOUGH TO MEASURE.
ALSO GIVEN TRAJECTORY OF EXISTING SHOWERS IN SOUTHWEST...VERY
DOUBTFUL IT WOULD EXTEND TO ANYWHERE SOUTH OF THE PLATTE RIVER.
OTHERWISE...WINDS BECOME WEST TO NORTHWEST THROUGH THE DAY WITH
BREEZY CONDITIONS AND WARM TEMPERATURES IN THE MID 60S TO LOWER 70S.
ANOTHER VERY SUBTLE WAVE MOVES OUT OF THE NORTHERN ROCKIES TONIGHT
WITH A VERY WEAK REINFORCING FRONTAL BOUNDARY. HAVE DOUBTS THAT
ANY PRECIP WOULD BE GENERATED AND WILL JUST HIT THE CLOUDS A
LITTLE HARDER OVERNIGHT.
THE NEXT WAVE OF INTEREST...WHICH IS CURRENTLY STILL OF THE
PACIFIC NORTHWEST COAST...MOVES INTO THE REGION SUNDAY AFTERNOON
AND NIGHT...BRINGING A FAIRLY DECENT CHANCE FOR RAIN...THUS HAVE
INCREASING CHANCES...EVENTUALLY REACHING 50 TO 70 PERCENT AS THE
WAVE MOVES THROUGH. INSTABILITY WILL ALSO BE INCREASING...THUS
HAVE THUNDER MENTIONED...LOOKS LIKE HEAVIEST PRECIP WITH THIS
ROUND WOULD SOUTH OF I80.
THERE WILL LIKELY BE A BREAK IN ANY PRECIP BY VERY LATE SUNDAY
NIGHT THROUGH MONDAY MORNING...BUT YET ANOTHER ROUND OF PRECIP IS
EXPECTED TO DEVELOP MONDAY NIGHT AND LINGER THROUGH MIDWEEK AS A
FAIRLY STRONG CLOSED LOW TROUGH DEVELOPS IN THE FOUR CORNERS
REGION. THIS WILL INITIALLY START AS SHOWERS AND THUNDERSTORMS...
ALTHOUGH IT SEEMS THAT THE BEST SEVERE THREAT IS SETTING UP JUST
SOUTH OF THE REGION ALONG/SOUTH OF THE KS/NE BORDER REGION. OUR
AREA APPEARS TO REMAIN ON THE COOLER SIDE OF THE BOUNDARY...WHICH
ALSO BRINGS IN A PRECIP TYPE ISSUE IN NORTHEAST NEBRASKA BY
TUESDAY NIGHT AND WEDNESDAY WHERE THE RAIN COULD MIX WITH SNOW.
THERE AREA STILL A FEW MODEL DISCREPANCIES THAT FAR OUT...ALL OF
WHICH WILL HAVE PRETTY BIG IMPACTS ON THE REGION...EITHER THE
POTENTIAL FOR MORE SNOW IN NORTHEAST NEBRASKA...OR THE INCREASED
POTENTIAL FOR A LITTLE MORE SEVERE THREAT A LITTLE FURTHER NORTH
INTO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...ALL OF WHICH WON`T BE
SOLVED UNTIL WE GET CLOSER TO THAT TIME FRAME. PRECIP COULD LINGER
THROUGH THURSDAY...BUT AGAIN THAT`S HIGHLY DEPENDENT ON LATER
MODEL SOLUTIONS.
DEWALD
&&
.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY EVENING. SOUTH WINDS
15 TO 25KT WILL TURN NORTHWEST AND INCREASE INTO 15 TO 30KT RANGE
BETWEEN 12Z AND 15Z AT ALL TAF SITES. THOSE WINDS SHOULD DIMINISH
TO NEAR 12KT AT 00Z. ONLY MID LEVEL CIGS AT OR ABOVE FL120 ARE
FORECAST.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1130 PM CDT FRI APR 5 2013
.UPDATE...
ISSUED AT 1130 PM CDT FRI APR 5 2013
CONFIDENCE CONTINUES TO INCREASE IN A FREEZING RAIN EVENT FOR
TONIGHT AND SATURDAY MORNING. 00Z GFS HAS COME IN WITH THE PRECIP
PLACEMENT EXACTLY WHERE THE NAM AND RAP ARE INDICATING (SEE
PREVIOUS UPDATED DISCUSSION). STILL NOT SURE HOW WIDESPREAD ICY
CONDITIONS WILL ACTUALLY BE...BUT SURFACE TEMPERATURES REMAIN AT
32F WHERE THE BAND OF RAINFALL IS EXPECTED TO MOVE THROUGH LATER
TONIGHT. TEMPERATURES WILL LIKELY BE ABOVE FREEZING ACROSS THE
EXTREME SOUTHERN FA...BUT THEY SHOULD REMAIN NEAR FREEZING JUST
TO THE NORTH WHERE THE MAJORITY OF PRECIP IS EXPECTED TO OCCUR.
00Z NAM/RAP/GFS ALSO INDICATE THE POTENTIAL FOR FZRA CHANGING OVER
TO SNOW ACROSS THE SE FA SATURDAY MORNING...WITH 1 TO 4 INCHES
POSSIBLE (DEPENDING ON EXACTLY WHEN THE SWITCHOVER OCCURS). GIVEN
THE LATEST DEVELOPMENTS...WILL ISSUE A FREEZING RAIN ADVISORY FOR
PORTIONS OF THE SOUTHERN FA...AND A WINTER WX ADVISORY FOR THE SE
FA.
WITH TEMPERATURES NEAR FREEZING...DO NOT THINK THAT ICE WILL
ACCUMULATE TOO QUICKLY WHICH SHOULD AVOID AN ICE STORM WARNING.
HOWEVER...TOTAL QPF WITHIN THE NARROW BAND EXPECTED TO BE 0.20 TO
0.40 INCHES...SO WILL NEED TO MONITOR CLOSELY. FURTHER TO THE
EAST..MODELS INDICATING SLIGHTLY HIGHER QPF AMOUNT OF 0.40 TO 0.60
INCHES...BUT SOME OF THIS SHOULD ALSO FALL AS SNOW.
UPDATE ISSUED AT 958 PM CDT FRI APR 5 2013
VERY TRICKY FORECAST FOR TONIGHT...ALTHOUGH CONFIDENCE HAS
INCREASED WITH PLACEMENT OF PRECIP. MID-LEVEL CIRCULATION WILL
PROPAGATE ACROSS THE SOUTHERN FA AFTER MIDNIGHT INTO SATURDAY
MORNING. THIS WILL LEAD TO AN AREA OF FRONTOGENESIS AND A BAND OF
MODERATE PRECIP (PWATS UP TO 0.75 INCHES). RAP...NAM...HRRR IN
AGREEMENT THAT THIS BAND WILL BE NARROW...AND IN THE GENERAL AREA
ALONG A LISBON TO FARGO TO PARK RAPIDS LINE. THE HI-RES MODELS
INDICATE 0.20 TO 0.40 INCHES WITHIN THIS BAND WHICH MAKES SENSE
GIVEN THE FORCING MECHANISM AND AVAILABLE MOISTURE. SURFACE
TEMPERATURES WITHIN THIS AREA ARE 31F TO 33F WITH DEWPOINT VALUES
SLIGHTLY LOWER. THE PRECIP WILL SURELY FALL AS LIQUID GIVEN VERY
WARM 850MB TEMPS...BUT NOT SURE HOW SFC TEMPS WILL REACT. GUIDANCE
IS INDICATING THE VALLEY WILL REMAIN WARM ENOUGH FOR ALL
RAIN...WITH FZRA POSSIBLE ON EITHER SIDE OF THE VALLEY. NOT SURE
HOW WIDESPREAD THE FZRA THREAT WILL BE...BUT WILL ISSUE A SPS TO
MENTION THE POSSIBILITY...AND MAY ISSUE AN ADVISORY LATER ONCE THE
BAND SETS UP.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 305 PM CDT FRI APR 5 2013
FORECAST CHALLENGE THROUGH THE SHORT TERM CONCERNS MAINLY
TEMPERATURES AND PCPN CHANCES/PHASE THROUGH TOMORROW. MODELS IN
RELATIVELY GOOD AGREEMENT WITH THERMAL PROFILES. CURRENT GFS
LOOKING TO BE THE ODD MODEL WITH RESPECT TO MAIN PCPN ORIENTATION
LATE TONIGHT AND WILL FOLLOW ECMWF/NAM/GEM POSITION.
CURRENT RETURNS FROM REGIONAL RADARS FROM E ND INTO W MN
ASSOCIATED WITH WARM ADVECTION REGIME AND WILL CONTINUE TO SPREAD
EAST THIS EVENING AHEAD OF APPROACHING WAVE. THE GENERAL CONSENSUS
AMONG MODELS IS TO CONTINUE TO ORGANIZE PCPN BAND ACROSS EASTERN
PTN OF FA SO WILL MAINTAIN HIGHER POPS THIS AREA. NOT LOOKING FOR
MUCH IN THE WAY OF ANY SIGNIFICANT ACCUMULATIONS.
AS WAVE PROPAGATES EAST OVERNIGHT SURFACE LOW PRESSURE WILL
ORGANIZE OVER NORTHERN/CENTRAL HIGH PLAINS AND TRACK ACROSS S SD.
ARCING BAND OF PCPN ON NORTH SIDE OF LOW WILL FOLLOW AFFECTING FA
AFT MIDNIGHT. GFS FARTHEST NORTH WITH PCPN BAND WITH OTHER MODELS TAKING
BAND ALONG ND/SD BORDER AREA INTO WEST CENTRAL MN. THERMAL PROFILES
IN THIS ZONE FAVOR POSSIBLE MIX HOWEVER WITH MIXING AND WARMTH OF
LOWER LEVLS DO NOT FEEL TEMPERATURES WILL DROP MUCH TONIGHT SO AM
THINKING MORE -RA VS FZRA AND WILL NOT ISSUE ANY HEADLINES. NOT
ONLY IS GFS FARTHER NORTH WITH PCPN BAND BUT COLDER AND HINTING AT
PSBL SNOW THIS AREA SO EVENTS WILL NEED TO BE MONITORED AS PHASE
UNCERTAIN.
LOW WILL CONTINUE TO PROPAGATE DUE EAST SATURDAY WITH PCPN LIKELY
CONFINED TO SE QUARTER OF FA. WILL MAINTAIN SOME LOW POPS
ELSEWHERE BUT OVER ALL REMAINDER OF FA WILL LIKELY BE DRY. COLD
ADVECTION IN WAKE OF LOW PASSAGE WILL RESULT IN BLO AVERAGE
TEMPERATURES BUT COULD SEE SOME MINOR MELTING. TEMPERATURES TO
DROP BLO FREEZING SATURDAY NIGHT AS HIGH PRESSURE BUILDS IN.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 305 CDT FRI APR 5 2013
HIGH SHIFTS EAST ON SUNDAY WITH SOME PCPN POSSIBLE IN WARM
ADVECTION ZONE AHEAD OF NEXT WEAK WAVE AND WILL MAINTAIN SOME MID
RANGE CHANCE POPS. PHASE AGAIN COULD BE AN ISSUE.
CONFIDENCE LOW ON PCPN TRENDS TO START OUT NEXT WORK WEEK. MODELS
FAR APART WITH ANY DETAILS SO WILL HOLD WITH INHERITED POPS.
THE EXTENDED PERIOD FOR THE FORECAST AREA WILL REMAIN UNDER THE
INFLUENCE OF AN UNSETTLED AND UNSEASONALLY COLD UPPER LEVEL TROUGH
PATTERN. THERE SHOULD BE LITTLE REDUCTION IN SURFACE SNOW COVER IN
THE RED RIVER BASIN THROUGH THE PERIOD. THUS...HIGH TEMPERATURES ARE
EXPECTED TO AVERAGE 15 TO 20 DEGREES BELOW SEASONAL NORMALS FOR THE
FIRST HALF OF APRIL. THIS TEMPERATURE REGIME WILL KEEP WINTER-LIKE
PRECIPITATION TYPES THROUGH THE PERIOD. DURING THE WARMER AFTERNOON
HOURS...THERE MAY BE RAIN AND SNOW MIXTURES. HOWEVER...PRECIPITATION
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1130 PM CDT FRI APR 5 2013
CIGS AND FZRA CHANCES WILL BE THE MAIN CONCERN. A SURFACE LOW
WILL TRACK ACROSS SOUTHERN SOUTH DAKOTA...CAUSING LOW LEVEL FLOW
TO REMAIN SOUTHEAST INTO SATURDAY MORNING. MVFR/IFR CIGS WEST OF
THE VALLEY ARE EXPECTED TO REMAIN IN PLACE OVERNIGHT...WITH VFR
CIGS ALONG AND EAST OF THE VALLEY. AS THE SYSTEM MOVES EAST
SATURDAY MORNING...LOWER CIGS WILL SPREAD EAST. THE BEST CHANCE
FOR FZRA WILL BE ACROSS SOUTHEAST NORTH DAKOTA INTO WEST CENTRAL
MINNESOTA...AFFECTING KFAR...AND POSSIBLY KBJI.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FREEZING RAIN ADVISORY UNTIL 9 AM CDT SATURDAY FOR NDZ038-039-
049-052-053.
MN...FREEZING RAIN ADVISORY UNTIL 9 AM CDT SATURDAY FOR MNZ002-003-
022-027-029>031.
WINTER WEATHER ADVISORY FROM 4 AM TO NOON CDT SATURDAY FOR
MNZ017-023-024-028-032.
&&
$$
UPDATE...TG
SHORT TERM...VOELKER
LONG TERM...BRAMER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
622 PM EDT SAT APR 6 2013
.SYNOPSIS...
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE CENTRAL
LAKES LATER TONIGHT. A COLD FRONT TRAILING THE LOW WILL MOVE
ACROSS THE LOCAL AREA ON SUNDAY MORNING. THE FRONT WILL STALL OVER
CENTRAL OHIO SUNDAY EVENING AND THEN MOVE LITTLE THROUGH MIDWEEK
AS WAVES OF LOW PRESSURE MOVE ALONG THE FRONT.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A LAKE BREEZE STRETCHING FROM LAKE TO CRAWFORD (PA) COUNTIES HAS
KEPT TEMPS NOTABLY COOLER THAN INLAND. THE GRADIENT WIND WILL
INCREASE THIS EVENING AND BY 00Z THE WINDS SHOULD BE OUT OF THE
SOUTH/SOUTHEAST FOR ALL AREAS. THIS WILL HAVE THE EFFECT OF
WARMING TEMPERATURES IN ERIE PA OVERNIGHT...RESULTING IN WARMER
OVERNIGHT TEMPERATURES THAN TODAY`S MAX. WARM AIR
ADVECTION...CLOUDS...AND STRONG WINDS WILL PREVENT MUCH COOLING
ELSEWHERE WITH MOST AREAS STAYING IN THE 40S AND LOWER 50S. THE
NEW GUIDANCE IS SHOWING A BROKEN LINE OF SHOWERS DEVELOPING AHEAD
OF THE FRONT AS IT MOVES INTO NW OH AFTER 06Z. IT LOOKS LIKE THIS
LINE WILL REACH ABOUT THE I-77 CORRIDOR BY DAYBREAK. HAVE TRIMMED
AND ADJUSTED POPS TO ACCOUNT FOR THIS SCENARIO. THE NEW GUIDANCE
INCLUDING THE LATEST HRRR ARE NOW SIMILAR SO CONFIDENCE IS HIGH
TODAY. MOST LOCATIONS WILL SEE AN HOUR OR TWO OF LIGHT PRECIP WITH
QPF TOTALS LESS THAN A TENTH OF AN INCH. UNTIL THE PRECIP
ARRIVES...THE THICKENING CLOUDS SHOULD KEEP TEMPS FROM DROPPING
TOO MUCH. WINDS WILL INCREASE MOST IN ANY PRECIPITATION WITH THE
FROPA DURING THE EARLY MORNING HOURS WITH GUSTS AROUND 30 MPH.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
IT WILL BE AN ACTIVE PERIOD FOR WEATHER. THE COLD FRONT SHOULD
PUSH SE OF THE AREA ON SUNDAY AND THEN STALL JUST TO THE SOUTH.
THIS FEATURE WILL EVENTUALLY COME BACK NORTH AS A WARM FRONT. THE
BIG QUESTION IS WHEN THAT WILL HAPPEN. MOST OF THE GUIDANCE SHOWS
A WAVE INTERACTING WITH THE FRONT ON MONDAY. THIS WILL FORCE THE
FRONT NORTH TO NEAR LAKE ERIE. EXPECT INSTABILITY TO BUILD AS THIS
HAPPENS. WILL NEED TO STICK WITH HIGH POPS FOR MONDAY WITH A
MENTION OF THUNDER AS WELL. UNSETTLED WEATHER WILL CONTINUE MONDAY
NIGHT INTO TUESDAY NIGHT AS WELL AS THE FRONT LINGERS. THE
INSTABILITY REALLY BUILDS ON TUESDAY WITH SOME SURFACE BASED CAPE
AND LI`S DIPPING BELOW ZERO. FOR NOW WILL LIMIT THUNDER CHANCES TO
THE DAYLIGHT HOURS BUT THAT MAY NEED TO BE EXPANDED DEPENDING ON
WHAT THE FRONT DOES. THE PERIOD SHOULD BE WARM WITH HIGHS IN THE
60S EXPECT NEAR THE IMMEDIATE LAKESHORE. OVERALL...THE CHANGES TO
THE FORECAST ARE PRETTY MINIMAL FROM THE PREVIOUS PACKAGE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
BEGINNING AT 12Z WEDNESDAY THE GFS AND ECMWF MODELS BEGIN TO DIVERGE
WITH THE GFS SHOWING A CLOSED SURFACE LOW OVER KANSAS, WHILE THE
ECMWF RESOLVES AN INVERTED THERMAL TROUGH OVER THE EASTERN CENTRAL
PLAINS. THE GFS TRACKS THE LOW INTO WESTERN INDIANA BY THURSDAY
MORNING SPREADING RAIN SHOWERS OVER THE AREA. RAIN ALSO BEGINS TO
FALL WITH THE ECMWF SOLUTION AROUND THIS TIME ALONG A STATIONARY
BOUNDARY. IT APPEARS THE ECMWF IS STRUGGLING TO RESOLVE THE SYSTEM,
PERHAPS DUE TO A BROAD MID-LEVEL RIDGE DEVELOPING OVER THE NE
QUADRANT. NONETHELESS A BAROCLINIC ZONE WILL DEVELOP AS THE SYSTEM
MATURES THROUGH THE WEEKEND. THE TEMPERATURE FORECAST WILL BE A
CHALLENGE AND WILL DEPEND ON THE TRACK AND DEVELOPMENT OF THE LOW.
THE ECMWF SOLUTION WILL YIELD LOWER DAYTIME TEMPS AS A BOUNDARY SETS
UP ACROSS CENTRAL OHIO. THE GFS HAS A MUCH BETTER DEFINED WARM
SECTOR ADVECTING WARMER AIR INTO THE REGION. FOR NOW GOING WITH A
BLEND OF THE 2 SOLUTIONS. WILL CONTINUE TO ADJUST FORECAST AS MODELS
HOPEFULLY CONVERGE ON A SIMILAR SOLUTION. AT THE LATEST BOTH MODELS
SHOW THE SYSTEM PASSING THROUGH THE AREA BY SATURDAY AFTERNOON WITH
THE ECMWF HINTING AT A BRIEF SHOT OF COOLER AIR ON THE BACKSIDE OF
THE SYSTEM. A FLURRY MAY BE POSSIBLE ACROSS THE HIGHER TERRAIN THAT
EVENING.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
VFR CIGS WILL CONTINUE INTO THE EVENING AS WINDS GRADUALLY
INCREASE AND BECOME GUSTY. EXPECT LOW LEVEL WIND SHEAR TONIGHT AS
A LOW LEVEL JET INCREASES TO OVER 50 KTS NEAR 2000 FEET FROM THE
SOUTHWEST. EXPECT MID AND HIGH CLOUDS TO INCREASE WITH SCATTERED
SHOWERS EXPECTED TO MOVE INTO THE REGION AFTER 06Z IN THE WEST AND
THEN GRADUALLY PROGRESS EASTWARD. EXPECT MAINLY VFR CIGS OVERNIGHT
AND VSBYS TO REMAIN VFR IN LIGHT SHOWERS. WIND SHEAR CONDITIONS
WILL END AROUND 12Z AS DEEPER MIXING OCCURS.
.OUTLOOK...NON VFR POSSIBLE MONDAY THROUGH TUESDAY NIGHT.
&&
.MARINE...
A COLD FRONT WILL SWEEP ACROSS THE LAKE TOWARD MORNING WITH FAIRLY
STRONG SOUTHERLY FLOW AHEAD OF THE FEATURE. EXPECTED STRONG
DOWNSLOPE WINDS OVER NORTHWEST PA TO DEVELOP OVER THE LAKE SHORE
FROM THE CITY OF ERIE TO RIPLEY NEW YORK OF ABOUT 30 KNOTS AFTER
MIDNIGHT. WINDS WILL INCREASE TO 15 TO 25 KNOTS ELSEWHERE OVER THE
LAKE. WITH COLD WATER IN PLACE A SOMEWHAT STABLE BOUNDARY LAYER WILL
INHIBIT SOME MIXING OF HIGHER WINDS OFF THE SURFACE. WILL ISSUE A
SMALL CRAFT ADVISORY FOR THIS EVENING UNTIL THE MIDDLE OF SUNDAY
AFTERNOON.
THE GRADIENT WILL RELAX SUNDAY AFTERNOON AND EVENING AS WEAK HIGH
PRESSURE BRIEFLY BUILDS OVER THE LAKE. THE FRONTAL BOUNDARY WILL
LIFT NORTH BACK ACROSS THE LAKE MONDAY NIGHT AND REMAIN NEAR THE
LAKE THROUGH MUCH OF THE WEEK WITH WIND SHIFTS AT TIMES AS IT
MEANDERS NEARBY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 4 PM EDT
SUNDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...JAMISON/KUBINA
SHORT TERM...KUBINA
LONG TERM...MAYERS
AVIATION...LAPLANTE
MARINE...LAPLANTE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
338 PM EDT SAT APR 6 2013
.SYNOPSIS...
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE CENTRAL
LAKES LATER TONIGHT. A COLD FRONT TRAILING THE LOW WILL MOVE
ACROSS THE LOCAL AREA ON SUNDAY MORNING. THE FRONT WILL STALL OVER
CENTRAL OHIO SUNDAY EVENING AND THEN MOVE LITTLE THROUGH MIDWEEK
AS WAVES OF LOW PRESSURE MOVE ALONG THE FRONT.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
QUITE A BIT OF HIGH CLOUDINESS REMAINS OVER THE AREA. EXPECT THE
CLOUDS TO GRADUALLY THICKEN OVERNIGHT AS A SURFACE COLD FRONT
APPROACHES FROM THE NW. VERY DRY AIR REMAINS OVER THE AREA WITH
DEWPOINTS IN THE TEENS. IF WINDS WERE STRONGER AND THERE WERE NO
CLOUDS MAY HAVE CONSIDERED A RED FLAG WARNING. AS IT IS...LOW
LEVEL MOISTURE SHOULD BEGIN TO INCREASE THIS EVENING. THE NEW
GUIDANCE IS SHOWING A BROKEN LINE OF SHOWERS DEVELOPING AHEAD OF
THE FRONT AS IT MOVES INTO NW OH AFTER 06Z. IT LOOKS LIKE THIS
LINE WILL REACH ABOUT THE I-77 CORRIDOR BY DAYBREAK. HAVE TRIMMED
AND ADJUSTED POPS TO ACCOUNT FOR THIS SCENARIO. THE NEW GUIDANCE
INCLUDING THE LATEST HRRR ARE NOW SIMILAR SO CONFIDENCE IS HIGH
TODAY. MOST LOCATIONS WILL SEE AN HOUR OR TWO OF LIGHT PRECIP WITH
QPF TOTALS LESS THAN A TENTH OF AN INCH. UNTIL THE PRECIP
ARRIVES...THE THICKENING CLOUDS SHOULD KEEP TEMPS FROM DROPPING
TOO MUCH. HAVE GONE A LITTLE WARMER THAN GUIDANCE FOR LOWS. WILL
HAVE TO WATCH WINDS OVERNIGHT AS THE SOUTHERLY FLOW WILL INCREASE
DRAMATICALLY. GUSTS TO 30 MPH APPEAR TO BE A GOOD BET...ESPECIALLY
IN THE GOOD DOWNSLOPE AREAS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
IT WILL BE AN ACTIVE PERIOD FOR WEATHER. THE COLD FRONT SHOULD
PUSH SE OF THE AREA ON SUNDAY AND THEN STALL JUST TO THE SOUTH.
THIS FEATURE WILL EVENTUALLY COME BACK NORTH AS A WARM FRONT. THE
BIG QUESTION IS WHEN THAT WILL HAPPEN. MOST OF THE GUIDANCE SHOWS
A WAVE INTERACTING WITH THE FRONT ON MONDAY. THIS WILL FORCE THE
FRONT NORTH TO NEAR LAKE ERIE. EXPECT INSTABILITY TO BUILD AS THIS
HAPPENS. WILL NEED TO STICK WITH HIGH POPS FOR MONDAY WITH A
MENTION OF THUNDER AS WELL. UNSETTLED WEATHER WILL CONTINUE MONDAY
NIGHT INTO TUESDAY NIGHT AS WELL AS THE FRONT LINGERS. THE
INSTABILITY REALLY BUILDS ON TUESDAY WITH SOME SURFACE BASED CAPE
AND LI`S DIPPING BELOW ZERO. FOR NOW WILL LIMIT THUNDER CHANCES TO
THE DAYLIGHT HOURS BUT THAT MAY NEED TO BE EXPANDED DEPENDING ON
WHAT THE FRONT DOES. THE PERIOD SHOULD BE WARM WITH HIGHS IN THE
60S EXPECT NEAR THE IMMEDIATE LAKESHORE. OVERALL...THE CHANGES TO
THE FORECAST ARE PRETTY MINIMAL FROM THE PREVIOUS PACKAGE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
BEGINNING AT 12Z WEDNESDAY THE GFS AND ECMWF MODELS BEGIN TO DIVERGE
WITH THE GFS SHOWING A CLOSED SURFACE LOW OVER KANSAS, WHILE THE
ECMWF RESOLVES AN INVERTED THERMAL TROUGH OVER THE EASTERN CENTRAL
PLAINS. THE GFS TRACKS THE LOW INTO WESTERN INDIANA BY THURSDAY
MORNING SPREADING RAIN SHOWERS OVER THE AREA. RAIN ALSO BEGINS TO
FALL WITH THE ECMWF SOLUTION AROUND THIS TIME ALONG A STATIONARY
BOUNDARY. IT APPEARS THE ECMWF IS STRUGGLING TO RESOLVE THE SYSTEM,
PERHAPS DUE TO A BROAD MID-LEVEL RIDGE DEVELOPING OVER THE NE
QUADRANT. NONETHELESS A BAROCLINIC ZONE WILL DEVELOP AS THE SYSTEM
MATURES THROUGH THE WEEKEND. THE TEMPERATURE FORECAST WILL BE A
CHALLENGE AND WILL DEPEND ON THE TRACK AND DEVELOPMENT OF THE LOW.
THE ECMWF SOLUTION WILL YIELD LOWER DAYTIME TEMPS AS A BOUNDARY SETS
UP ACROSS CENTRAL OHIO. THE GFS HAS A MUCH BETTER DEFINED WARM
SECTOR ADVECTING WARMER AIR INTO THE REGION. FOR NOW GOING WITH A
BLEND OF THE 2 SOLUTIONS. WILL CONTINUE TO ADJUST FORECAST AS MODELS
HOPEFULLY CONVERGE ON A SIMILAR SOLUTION. AT THE LATEST BOTH MODELS
SHOW THE SYSTEM PASSING THROUGH THE AREA BY SATURDAY AFTERNOON WITH
THE ECMWF HINTING AT A BRIEF SHOT OF COOLER AIR ON THE BACKSIDE OF
THE SYSTEM. A FLURRY MAY BE POSSIBLE ACROSS THE HIGHER TERRAIN THAT
EVENING.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
VFR CIGS WILL CONTINUE INTO THE EVENING AS WINDS GRADUALLY
INCREASE AND BECOME GUSTY. EXPECT LOW LEVEL WIND SHEAR TONIGHT AS
A LOW LEVEL JET INCREASES TO OVER 50 KTS NEAR 2000 FEET FROM THE
SOUTHWEST. EXPECT MID AND HIGH CLOUDS TO INCREASE WITH SCATTERED
SHOWERS EXPECTED TO MOVE INTO THE REGION AFTER 06Z IN THE WEST AND
THEN GRADUALLY PROGRESS EASTWARD. EXPECT MAINLY VFR CIGS OVERNIGHT
AND VSBYS TO REMAIN VFR IN LIGHT SHOWERS. WIND SHEAR CONDITIONS
WILL END AROUND 12Z AS DEEPER MIXING OCCURS.
.OUTLOOK...NON VFR POSSIBLE MONDAY THROUGH TUESDAY NIGHT.
&&
.MARINE...
A COLD FRONT WILL SWEEP ACROSS THE LAKE TOWARD MORNING WITH FAIRLY
STRONG SOUTHERLY FLOW AHEAD OF THE FEATURE. EXPECTED STRONG
DOWNSLOPE WINDS OVER NORTHWEST PA TO DEVELOP OVER THE LAKE SHORE
FROM THE CITY OF ERIE TO RIPLEY NEW YORK OF ABOUT 30 KNOTS AFTER
MIDNIGHT. WINDS WILL INCREASE TO 15 TO 25 KNOTS ELSEWHERE OVER THE
LAKE. WITH COLD WATER IN PLACE A SOMEWHAT STABLE BOUNDARY LAYER WILL
INHIBIT SOME MIXING OF HIGHER WINDS OFF THE SURFACE. WILL ISSUE A
SMALL CRAFT ADVISORY FOR THIS EVENING UNTIL THE MIDDLE OF SUNDAY
AFTERNOON.
THE GRADIENT WILL RELAX SUNDAY AFTERNOON AND EVENING AS WEAK HIGH
PRESSURE BRIEFLY BUILDS OVER THE LAKE. THE FRONTAL BOUNDARY WILL
LIFT NORTH BACK ACROSS THE LAKE MONDAY NIGHT AND REMAIN NEAR THE
LAKE THROUGH MUCH OF THE WEEK WITH WIND SHIFTS AT TIMES AS IT
MEANDERS NEARBY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 4 PM EDT
SUNDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...MAYERS
AVIATION...LAPLANTE
MARINE...LAPLANTE
AREA FORECAST DISCUSSION
NWS TULSA OK
638 PM CDT SUN APR 7 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
MVFR CEILINGS AT THE OKLAHOMA TAF SITES WILL PERSIST INTO
MONDAY...WITH CEILINGS LOWERING TO MVFR AT THE ARKANSAS SITES
LATER TONIGHT. VFR CONDITIONS WILL RETURN TO THE NORTHEAST
OKLAHOMA SITES LATER MONDAY AFTERNOON...WITH CEILINGS REMAINING
MVFR AT KMLC AND AT THE ARKANSAS SITES.
&&
.PREV DISCUSSION... /ISSUED 337 PM CDT SUN APR 7 2013/
DISCUSSION...
CURRENT SURFACE ANALYSIS SHOWS A SUBTLE PRESSURE TROUGH THAT LIES
WEST-EAST ALONG THE KS BORDER. MEANWHILE...MOISTURE CONTINUES TO
SLOWLY INCREASE AND SURGE NORTH. AN ISOLATED SUPERCELL DEVELOPED
ON THE NORTH SIDE OF THIS FEATURE AND CONTINUES EAST ACROSS KS.
THERE IS POTENTIAL LATER THIS AFTERNOON FOR AN ISOLATED STORM TO
DEVELOP OVER FAR NW OK/SW-S CNTRL KS AND TRACK EAST TOWARD NE OK.
THE MOST RECENT AVAILABLE RUN OF THE HRRR HAS BACKED OFF ON THIS
POSSIBILITY BUT IT IS STILL WORTH WATCHING. ANY UPDRAFT THAT CAN
SUSTAIN ITSELF WILL LIKELY ROTATE...GIVEN ~50 KTS OF WESTERLY DEEP
LAYER SHEAR. THE RIGHT MOVING BUNKERS SUPERCELL VECTOR HAS A
MOTION JUST NORTH OF DUE EAST AT 20 KTS. THIS HAS BACKED FROM
EARLIER TODAY...MOST LIKELY DUE TO STRENGTHENING WSW FLOW IN
ADVANCE OF AN IMPULSE OVER NM PER WV IMAGERY. SO THE BEST
POTENTIAL FOR SEVERE STORMS WILL BE NEAR THE KS BORDER AND MAINLY
WEST OF HIGHWAY 75 THROUGH THIS EVENING. VERY LARGE HAIL TO
BASEBALL SIZE IS CERTAINLY POSSIBLE...AND DUE TO STRENGTHENING
0-1KM SHEAR AN ISOLATED TORNADO OR TWO COULD ACCOMPANY A SUPERCELL
IF IT HAPPENED TO PAY US A VISIT THIS EVENING. LOOKS LIKE MORE
WIDESPREAD AND MAINLY ELEVATED STORMS WILL GET ALONG AND NORTH OF
SURFACE TROUGH TOWARD 06Z AS STRENGTHENING LLJ FOCUSES ISENTROPIC
LIFT. THERE IS SOME UNCERTAINTY IN HOW FAR SOUTH TO PUT RAIN
CHANCES...AS OUR LOCAL MODEL DEVELOPS STORMS A BIT FARTHER SOUTH.
FOR NOW WILL HEDGE AND PUT SLIGHT CHCS DOWN TO NEAR I-40.
THE CAP STRENGTHENS ON MONDAY AND THE BOUNDARY TO OUR NORTH
CONSOLIDATES WITH A STRENGTHENING WARM FRONT NEAR THE KS/NEB
BORDER. CHANCES FOR ANY STORMS TOO LOW TO MENTION IN THE FORECAST.
IT IS A HIGHLY CONDITIONAL SETUP (PROBABLY THE BEST OF THE WEEK)...BUT
LOW PROB OF OCCURRENCE.
THE NEXT BIG CHALLENGE WILL BE LATE TUESDAY INTO WEDNESDAY. THE
DATA TODAY HAS NOT REALLY CHANGED MY FORECAST REASONING FROM
YESTERDAY MUCH AT ALL. MODEL SOUNDINGS STILL SHOW A DECENT CAP IN
THE WARM SECTOR TUESDAY...SO IT WILL BE DIFFICULT TO GET STORMS TO GO
WITH THE MAIN UPPER TROUGH STILL WELL WEST AND LACK OF ANY
FOCUSING BOUNDARIES IN OUR AREA. IF A STORM DOES GO IN THE WARM
SECTOR...IT WOULD LIKELY BE BAD...BUT ODDS ARE PRETTY LOW. THE
MOST LIKELY SCENARIO IS FRONTAL FORCING ALONG A SURGING COLD FRONT
WILL PROVIDE THE LIFT NEEDED FOR CONVECTION. HOWEVER...SINCE UPPER
TROUGH IS COMING OUT WITH A POSITIVE TILT...THE UPPER FLOW WILL BE
PARALLEL TO THE FRONT...THUS STORMS THAT DEVELOP WITH THE FRONT
WILL TEND TO BE UNDERCUT QUICKLY. THE ECMWF CONTINUES TO SHOW
ALMOST ALL QPF ON THE COOL SIDE OF THE FRONT...INDICATIVE OF THIS
VERY SCENARIO. I`M NOT SAYING THERE WILL NOT BE SEVERE
WEATHER...BUT THE TENDENCY FOR STORMS TO BE UNDERCUT WILL LIMIT
THE SEVERE POTENTIAL. POST-FRONTAL RAIN AND STORMS ARE FORECAST TO
CONTINUE THRU WEDNESDAY...TAPERING OFF BY THURSDAY MORNING.
TEMPS WILL COOL OFF BEHIND THE FRONT...AND WILL REMAIN THAT WAY
FOR THE LATTER HALF OF THE WEEK AND INTO THE FIRST PART OF THE
WEEKEND. A SUBTLE WAVE WILL PASS THRU THE PLAINS SATURDAY...WITH
THE MAIN EFFECT BEING MORE CLOUD COVER. ONCE THAT PASSES...UPPER
FLOW TRANSITIONS TO SW AND LEE SIDE LOW PRESSURE DEVELOPS OVER SW
KS/SE CO. SOUTHWEST WINDS WILL PREVAIL HERE AND TEMPS WILL REBOUND
QUICKLY BY NEXT SUNDAY.
LACY
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...05
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
849 PM EDT SUN APR 7 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE REGION THIS
EVENING...BUT STALL OUT ALONG THE MARYLAND BORDER. THE FRONT WILL
REVERSE COURSE AND RETURN BACK TO THE NORTH OF THE AREA ON MONDAY.
ABOVE NORMAL TEMPERATURES ARE EXPECTED TO PREVAIL FOR MUCH OF THE
COMING WEEK. OCCASIONAL SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED
IN FAST...FLAT FLOW ALOFT. COOLER AND DRIER CONDITIONS ARE EXPECTED
FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATED THE GRIDS AND ZONE TEXT FOR BRIEF TSRA ACROSS MAINLY THE
SW ZONES THIS EVENING.
COLD FRONT SLIDING THROUGH THE NW MTNS EARLY THIS EVENING WILL
BISECT THE STATE FROM NW TO SE BY 03Z MONDAY BEFORE STALLING OUT
NEAR THE MASON DIXON LINE AROUND DAYBREAK MONDAY.
THE BEST 925-850 MB MOISTURE CONVERGENCE AND RELATIVELY DEEPER UVVEL
BENEATH THE RIGHT ENTRANCE REGION OF A 75 KT JETLET AT 300 MB WILL
BE FOCUSED ACROSS THE LAUREL HIGHLANDS AND SCENT MTNS OVER THE NEXT
SEVERAL HOURS. THIS WILL LEAD TO A LIKELIHOOD OF A FEW SHOWERS IN
THAT PORTION OF THE CWA /WITH SEVERAL HUNDREDTHS OF AN INCH OF
RAINFALL/...WHILE OTHER LOCATIONS WILL SEE ISOLATED TO SCATTERED
BRIEF SHOWERS AT MOST /WITH MARGINALLY MEASURABLE AMOUNTS/.
LATEST HRRR PAINTS THIS SCENARIO PRETTY ACCURATELY AND SHOWS THE
LAST VESTIGES OF THE LIGHT SHOWERS ACROSS THE LOWER SUSQ VALLEY
AROUND 05-06Z MONDAY.
ADDITIONALLY...A TRANSIENT POCKET OF MARGINALLY UNSTABLE LLVL AIR
/WITH SFC-925 MB BASED LIFTED INDICES SLIGHTLY UNDER 0C/ WILL
SLIDE ACROSS THE SOUTHERN HALF OF THE STATE THROUGH
03Z...SUPPORTING SOME BRIEF/ISOLATED...LOW-TOPPED AND HIGH-BASED
TSRA.
WILL KEEP TEMPS UNSEASONABLY MILD THIS EVENING...BUT AS THE ACTUAL
COLDER AIRMASS ROLLS IN ACROSS THE LAKES...IT SHOULD ALLOW THE NRN
MTS TO GET INTO THE 40S BY MIDNIGHT.
CLOUDS REMAIN STUBBORN AS THE FRONT SLOWS ITS SWD DRIFT LATE TONIGHT
NEAR THE MASON DIXON LINE. HOWEVER...THE NRN THIRD OF THE AREA WILL
CLEAR OUT UNDER NICE DRYING. WILL THAT CLEARING HOLD IS A GOOD
QUESTION SOME LOWER CLOUDS ARE POSSIBLE IN NY STATE AS THE WINDS DO
SWITCH TO THE NORTH LATE AT NIGHT. BUT...AT THIS POINT...THE
DOWNSLOPE LLVL FLOW...THE LACK OF RAINFALL AND LLVL MSTR WILL
HAMPER THE SWRD ADVANCE OF THESE CLOUDS. WILL JUST HINT AT SOME
CLOUDS RETURNING TO THE NERN MTS.
TEMPS BY DAYBREAK MONDAY WILL SETTLE INTO THE LOWER TO MID 30S
ACROSS THE NRN MTNS...WHILE THE CENTRAL AND SOUTHERN ZONES SEE LOW
TEMPS IN THE MID TO UPPER 40S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
THE FRONT STALLS OVER THE SRN BORDER AND WAITS FOR A TROUGH OVER THE
MIDWEST TO BUBBLE NORTH INTO THE UPPER GREAT LAKES ON MONDAY. THIS
WILL PUSH SOME SHOWERS ACROSS THE WESTERN HALF OF THE AREA DURING
THE DAY. HEIGHTS RISE AND STRONG WARM ADVECTION WILL PUMP UP THE
TEMPS. MANY PLACES IN THE SOUTH COULD GET NEAR OR ABOVE 70F. THE
CLOUDS OVER THE WEST COULD KEEP THEM COOLER...BUT THAT WOULD STILL
BE ABOVE NORMAL. BESIDES...THE WARM SECTOR WILL RUN INTO THE WESTERN
MTS FIRST. WILL MAKE A GENERAL/HOMOGENEOUS 65-70F FORECAST FOR MON
AFTN. SOME THUNDER IS POSSIBLE ON MONDAY...AS MOISTURE INCREASES
ENOUGH...BUT WILL KEEP MENTIONS TO THE WESTERN HALF OF THE AREA FOR
THE AFTN.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MAJOR CHANGES MADE TO PACKAGE.
DID UP TEMPS FOR MUCH OF THE PERIOD MONDAY INTO THU...AS MUCH
OF CENTRAL PA WILL BE IN THE WARM AIR.
ALSO TRIMMED POPS HERE AND THERE. WAS THINKING THIS WOULD BE
A WET WEEK...ESPECIALLY FOR N PA...BUT NOW IT LOOKS LIKE MUCH
OF THE RAIN WILL BE MUCH FURTHER NORTH...MOST LIKELY CANADA.
WAS UP IN WESTERN NY YESTERDAY...ABOUT AS DRY AS I CAN RECALL
FOR EARLY APRIL.
IT WILL BE INTERESTING TO SEE HOW WARM WE GET BY MID WEEK...GIVEN
THE CHANGE IN THE UPPER LVL PATTERN. WILL SEE HOW THIS PLAYS OUT
ESPECIALLY GIVEN THE RECENT HIGH LATITUDE BLOCKING AND COLD SPELL.
TEMPS COULD PUSH UPPER 80S SOUTHERN PA BY WED...GIVEN 850 MB
TEMPS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A COLD FRONT...LOCATED OVER NORTHWEST PA AT 00Z...WILL SETTLE
SOUTH ACROSS THE REGION THIS EVENING...THEN STALL OUT NEAR THE
MASON DIXON LINE LATE TONIGHT. RADAR AT 00Z SHOWS SCT SHRA/TSRA
HAVE DEVELOPED JUST AHEAD OF THE FRONT ACROSS CENTRAL PA...WHICH
COULD PRODUCE A BRIEF VSBY REDUCTION IN A FEW SPOTS EARLY THIS
EVENING. HOWEVER...DWPT DEPRESSIONS REMAIN QUITE HIGH...SO EXPECT
MOST AIRFIELDS TO REMAIN VFR THROUGH THE ENTIRE EVENING.
BIGGEST AVIATION CONCERN IN THE NEAR TERM WILL BE THE POSSIBILITY
OF SOME LATE NIGHT FOG ACROSS SOUTHERN PA. MDL DATA SHOWING A
TONGUE OF RELATIVELY MOIST AIR IN VICINITY OF DYING COLD FRONT
LAYING OUT ACROSS SOUTHERN PA LATE TONIGHT. THIS MOISTURE...COMBINED
WITH DIMINISHING WINDS...COULD SET THE STAGE FOR PATCHY RADIATION
FOG ARND DAWN ACROSS SOUTHERN PA...ESP IN THOSE FEW SPOTS THAT
RECEIVE RAINFALL THIS EVENING. CONFIDENCE NOT HIGH ENOUGH TO
MENTION IN TAFS YET...BUT WILL HAVE TO MONITOR OVERNIGHT.
GUSTY SW WINDS AHEAD OF THE CDFRNT EARLY THIS EVENING WILL WEAKEN
AS THE DYING FRONT WASHES OUT ACROSS SOUTHERN PA LATER THIS
EVENING.
ANY EARLY FOG SHOULD LIFT SHORTLY AFTER SUNRISE MONDAY. FOCUS
WILL THEN SHIFT TOWARD THE LIKELIHOOD OF SCT AFTN CONVECTION
ASSOCIATED WITH FRONTAL BOUNDARY LIFTING BACK NORTH ACROSS THE
REGION AS A WARM FRONT. AN AFTN SHRA/TSRA COULD BRIEFLY LOWER
VSBYS...DESPITE WIDESPREAD VFR CONDS.
.OUTLOOK...
TUE...EARLY AM LOW CIGS POSS W MTNS. ISOLD TSRA IMPACTS POSS NORTH.
WED...EARLY AM LOW CIGS POSS NW MTNS. ISOLD TSRA IMPACTS POSS NORTH.
THU...CHC OF PM TSRA IMPACTS.
FRI...AM RAIN/LOW CIGS POSS.
&&
.FIRE WEATHER...
SOUTH TO SW WINDS WILL GUST TO AROUND 20 MPH THIS EVENING BEFORE
DIMINISHING...THEN SHIFTING TO THE WNW AT AROUND 10 MPH FROM NW TO
SE OVERNIGHT. THE DRY FUELS...AND RH IN THE 35-40 PERCENT RANGE WILL
COMBINE WITH THE WIND TO CREATE A SLIGHTLY ELEVATED CHC FOR WILDFIRE
SPREAD THIS EVENING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...MARTIN/STEINBUGL
AVIATION...FITZGERALD
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
748 PM EDT SUN APR 7 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE REGION THIS
EVENING...BUT STALL OUT ALONG THE MARYLAND BORDER. THE FRONT WILL
REVERSE COURSE AND RETURN BACK TO THE NORTH OF THE AREA ON MONDAY.
ABOVE NORMAL TEMPERATURES ARE EXPECTED TO PREVAIL FOR MUCH OF THE
COMING WEEK. OCCASIONAL SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED
IN FAST...FLAT FLOW ALOFT. COOLER AND DRIER CONDITIONS ARE EXPECTED
FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATED THE GRIDS AND ZONE TEXT FOR BRIEF TSRA ACROSS MAINLY THE
SW ZONES THIS EVENING.
COLD FRONT SLIDING THROUGH THE NW MTNS EARLY THIS EVENING WILL
BISECT THE STATE FROM NW TO SE BY 03Z MONDAY BEFORE STALLING OUT
NEAR THE MASON DIXON LINE AROUND DAYBREAK MONDAY.
THE BEST 925-850 MB MOISTURE CONVERGENCE AND RELATIVELY DEEPER UVVEL
BENEATH THE RIGHT ENTRANCE REGION OF A 75 KT JETLET AT 300 MB WILL
BE FOCUSED ACROSS THE LAUREL HIGHLANDS AND SCENT MTNS OVER THE NEXT
SEVERAL HOURS. THIS WILL LEAD TO A LIKELIHOOD OF A FEW SHOWERS IN
THAT PORTION OF THE CWA /WITH SEVERAL HUNDREDTHS OF AN INCH OF
RAINFALL/...WHILE OTHER LOCATIONS WILL SEE ISOLATED TO SCATTERED
BRIEF SHOWERS AT MOST /WITH MARGINALLY MEASURABLE AMOUNTS/.
LATEST HRRR PAINTS THIS SCENARIO PRETTY ACCURATELY AND SHOWS THE
LAST VESTIGES OF THE LIGHT SHOWERS ACROSS THE LOWER SUSQ VALLEY
AROUND 05-06Z MONDAY.
ADDITIONALLY...A TRANSIENT POCKET OF MARGINALLY UNSTABLE LLVL AIR
/WITH SFC-925 MB BASED LIFTED INDICES SLIGHTLY UNDER 0C/ WILL
SLIDE ACROSS THE SOUTHERN HALF OF THE STATE THROUGH
03Z...SUPPORTING SOME BRIEF/ISOLATED...LOW-TOPPED AND HIGH-BASED
TSRA.
WILL KEEP TEMPS UNSEASONABLY MILD THIS EVENING...BUT AS THE ACTUAL
COLDER AIRMASS ROLLS IN ACROSS THE LAKES...IT SHOULD ALLOW THE NRN
MTS TO GET INTO THE 40S BY MIDNIGHT.
CLOUDS REMAIN STUBBORN AS THE FRONT SLOWS ITS SWD DRIFT LATE TONIGHT
NEAR THE MASON DIXON LINE. HOWEVER...THE NRN THIRD OF THE AREA WILL
CLEAR OUT UNDER NICE DRYING. WILL THAT CLEARING HOLD IS A GOOD
QUESTION SOME LOWER CLOUDS ARE POSSIBLE IN NY STATE AS THE WINDS DO
SWITCH TO THE NORTH LATE AT NIGHT. BUT...AT THIS POINT...THE
DOWNSLOPE LLVL FLOW...THE LACK OF RAINFALL AND LLVL MSTR WILL
HAMPER THE SWRD ADVANCE OF THESE CLOUDS. WILL JUST HINT AT SOME
CLOUDS RETURNING TO THE NERN MTS.
TEMPS BY DAYBREAK MONDAY WILL SETTLE INTO THE LOWER TO MID 30S
ACROSS THE NRN MTNS...WHILE THE CENTRAL AND SOUTHERN ZONES SEE LOW
TEMPS IN THE MID TO UPPER 40S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
THE FRONT STALLS OVER THE SRN BORDER AND WAITS FOR A TROUGH OVER THE
MIDWEST TO BUBBLE NORTH INTO THE UPPER GREAT LAKES ON MONDAY. THIS
WILL PUSH SOME SHOWERS ACROSS THE WESTERN HALF OF THE AREA DURING
THE DAY. HEIGHTS RISE AND STRONG WARM ADVECTION WILL PUMP UP THE
TEMPS. MANY PLACES IN THE SOUTH COULD GET NEAR OR ABOVE 70F. THE
CLOUDS OVER THE WEST COULD KEEP THEM COOLER...BUT THAT WOULD STILL
BE ABOVE NORMAL. BESIDES...THE WARM SECTOR WILL RUN INTO THE WESTERN
MTS FIRST. WILL MAKE A GENERAL/HOMOGENEOUS 65-70F FORECAST FOR MON
AFTN. SOME THUNDER IS POSSIBLE ON MONDAY...AS MOISTURE INCREASES
ENOUGH...BUT WILL KEEP MENTIONS TO THE WESTERN HALF OF THE AREA FOR
THE AFTN.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MAJOR CHANGES MADE TO PACKAGE.
DID UP TEMPS FOR MUCH OF THE PERIOD MONDAY INTO THU...AS MUCH
OF CENTRAL PA WILL BE IN THE WARM AIR.
ALSO TRIMMED POPS HERE AND THERE. WAS THINKING THIS WOULD BE
A WET WEEK...ESPECIALLY FOR N PA...BUT NOW IT LOOKS LIKE MUCH
OF THE RAIN WILL BE MUCH FURTHER NORTH...MOST LIKELY CANADA.
WAS UP IN WESTERN NY YESTERDAY...ABOUT AS DRY AS I CAN RECALL
FOR EARLY APRIL.
IT WILL BE INTERESTING TO SEE HOW WARM WE GET BY MID WEEK...GIVEN
THE CHANGE IN THE UPPER LVL PATTERN. WILL SEE HOW THIS PLAYS OUT
ESPECIALLY GIVEN THE RECENT HIGH LATITUDE BLOCKING AND COLD SPELL.
TEMPS COULD PUSH UPPER 80S SOUTHERN PA BY WED...GIVEN 850 MB
TEMPS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A COLD FRONT...LOCATED OVER NORTHWEST PA AT 23Z...WILL SETTLE SOUTH
ACROSS THE REGION THIS EVENING...THEN STALL OUT NEAR THE MASON
DIXON LINE LATE TONIGHT. RADAR AT 23Z SHOWS SCT SHRA HAVE
DEVELOPED JUST AHEAD OF THE FRONT ACROSS CENTRAL PA...WHICH COULD
PRODUCE A BRIEF VSBY REDUCTION IN A FEW SPOTS EARLY THIS EVENING.
HOWEVER...DWPT DEPRESSIONS REMAIN QUITE HIGH...SO EXPECT MOST
AIRFIELDS TO REMAIN VFR THROUGH THE ENTIRE EVENING.
BIGGEST AVIATION CONCERN IN THE NEAR TERM WILL BE THE POSSIBILITY
OF SOME LATE NIGHT LOW CIGS/FOG ACROSS SOUTHWEST PA...INCLUDING
JST AND AOO. MDL DATA SHOWING A TONGUE OF RELATIVELY MOIST AIR IN
VICINITY OF DYING COLD FRONT LAYING OUT ACROSS SOUTHERN PA LATE
TONIGHT. THIS MOISTURE...COMBINED WITH DIMINISHING WINDS...COULD
SET THE STAGE FOR PATCHY RADIATION FOG ARND DAWN AT JST AND AOO.
GUSTY WINDS EARLY THIS EVENING WILL WEAKEN AS THE DYING FRONT
WASHES OUT ACROSS SOUTHERN PA LATER THIS EVENING. LIGHT WIND ON
MONDAY AS THE FRONT TAKES A WHILE TO GO BACK NORTH.
.OUTLOOK...
TUE-WED...MAINLY VFR. ISOLD SHRA POSS.
THU-FRI...CFROPA. MVFR/IFR POSS IN TS/SHRA.
&&
.FIRE WEATHER...
SOUTH TO SW WINDS WILL GUST TO AROUND 20 MPH THIS EVENING BEFORE
DIMINISHING...THEN SHIFTING TO THE WNW AT AROUND 10 MPH FROM NW TO
SE OVERNIGHT. THE DRY FUELS...AND RH IN THE 35-40 PERCENT RANGE WILL
COMBINE WITH THE WIND TO CREATE A SLIGHTLY ELEVATED CHC FOR WILDFIRE
SPREAD THIS EVENING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...MARTIN/STEINBUGL
AVIATION...DANGELO/FITZGERALD
FIRE WEATHER...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
655 PM EDT SUN APR 7 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE REGION THIS
EVENING...BUT STALL OUT ALONG THE MARYLAND BORDER. THE FRONT WILL
REVERSE COURSE AND RETURN BACK TO THE NORTH OF THE AREA ON MONDAY.
ABOVE NORMAL TEMPERATURES ARE EXPECTED TO PREVAIL FOR MUCH OF THE
COMING WEEK. OCCASIONAL SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED
IN FAST...FLAT FLOW ALOFT. COOLER AND DRIER CONDITIONS ARE EXPECTED
FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
COLD FRONT SLIDING THROUGH THE NW MTNS EARLY THIS EVENING WILL
BISECT THE STATE FROM NW TO SE BY 03Z MONDAY BEFORE STALLING OUT
NEAR THE MASON DIXON LINE AROUND DAYBREAK MONDAY.
THE BEST 925-850 MB MOISTURE CONVERGENCE AND RELATIVELY DEEPER UVVEL
BENEATH THE RIGHT ENTRANCE REGION OF A 75 KT JETLET AT 300 MB WILL
BE FOCUSED ACROSS THE LAUREL HIGHLANDS AND SCENT MTNS OVER THE NEXT
SEVERAL HOURS. THIS WILL LEAD TO A LIKELIHOOD OF A FEW SHOWERS IN
THAT PORTION OF THE CWA /WITH SEVERAL HUNDREDTHS OF AN INCH OF
RAINFALL/...WHILE OTHER LOCATIONS WILL SEE ISOLATED TO SCATTERED
BRIEF SHOWERS AT MOST /WITH MARGINALLY MEASURABLE AMOUNTS/.
LATEST HRRR PAINTS THIS SCENARIO PRETTY ACCURATELY AND SHOWS THE
LAST VESTIGES OF THE LIGHT SHOWERS ACROSS THE LOWER SUSQ VALLEY
AROUND 05-06Z MONDAY.
WILL KEEP TEMPS UNSEASONABLY MILD THIS EVENING...BUT AS THE ACTUAL
COLDER AIRMASS ROLLS IN ACROSS THE LAKES...IT SHOULD ALLOW THE NRN
MTS TO GET INTO THE 40S BY MIDNIGHT.
CLOUDS REMAIN STUBBORN AS THE FRONT SLOWS ITS SWD DRIFT LATE TONIGHT
NEAR THE MASON DIXON LINE. HOWEVER...THE NRN THIRD OF THE AREA WILL
CLEAR OUT UNDER NICE DRYING. WILL THAT CLEARING HOLD IS A GOOD
QUESTION SOME LOWER CLOUDS ARE POSSIBLE IN NY STATE AS THE WINDS DO
SWITCH TO THE NORTH LATE AT NIGHT. BUT...AT THIS POINT...THE
DOWNSLOPE LLVL FLOW...THE LACK OF RAINFALL AND LLVL MSTR WILL
HAMPER THE SWRD ADVANCE OF THESE CLOUDS. WILL JUST HINT AT SOME
CLOUDS RETURNING TO THE NERN MTS.
TEMPS BY DAYBREAK MONDAY WILL SETTLE INTO THE LOWER TO MID 30S
ACROSS THE NRN MTNS...WHILE THE CENTRAL AND SOUTHERN ZONES SEE LOW
TEMPS IN THE MID TO UPPER 40S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
THE FRONT STALLS OVER THE SRN BORDER AND WAITS FOR A TROUGH OVER THE
MIDWEST TO BUBBLE NORTH INTO THE UPPER GREAT LAKES ON MONDAY. THIS
WILL PUSH SOME SHOWERS ACROSS THE WESTERN HALF OF THE AREA DURING
THE DAY. HEIGHTS RISE AND STRONG WARM ADVECTION WILL PUMP UP THE
TEMPS. MANY PLACES IN THE SOUTH COULD GET NEAR OR ABOVE 70F. THE
CLOUDS OVER THE WEST COULD KEEP THEM COOLER...BUT THAT WOULD STILL
BE ABOVE NORMAL. BESIDES...THE WARM SECTOR WILL RUN INTO THE WESTERN
MTS FIRST. WILL MAKE A GENERAL/HOMOGENEOUS 65-70F FORECAST FOR MON
AFTN. SOME THUNDER IS POSSIBLE ON MONDAY...AS MOISTURE INCREASES
ENOUGH...BUT WILL KEEP MENTIONS TO THE WESTERN HALF OF THE AREA FOR
THE AFTN.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MAJOR CHANGES MADE TO PACKAGE.
DID UP TEMPS FOR MUCH OF THE PERIOD MONDAY INTO THU...AS MUCH
OF CENTRAL PA WILL BE IN THE WARM AIR.
ALSO TRIMMED POPS HERE AND THERE. WAS THINKING THIS WOULD BE
A WET WEEK...ESPECIALLY FOR N PA...BUT NOW IT LOOKS LIKE MUCH
OF THE RAIN WILL BE MUCH FURTHER NORTH...MOST LIKELY CANADA.
WAS UP IN WESTERN NY YESTERDAY...ABOUT AS DRY AS I CAN RECALL
FOR EARLY APRIL.
IT WILL BE INTERESTING TO SEE HOW WARM WE GET BY MID WEEK...GIVEN
THE CHANGE IN THE UPPER LVL PATTERN. WILL SEE HOW THIS PLAYS OUT
ESPECIALLY GIVEN THE RECENT HIGH LATITUDE BLOCKING AND COLD SPELL.
TEMPS COULD PUSH UPPER 80S SOUTHERN PA BY WED...GIVEN 850 MB
TEMPS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
LITTLE OR NO REDUCTIONS BELOW VFR ARE EXPECTED THIS PERIOD. VERY
LITTLE MOISTURE IS POOLING AHEAD OF A COLD FRONT WHICH WILL MOVE
SOUTHWARD THROUGH THE AREA THIS EVENING AND EARLY TONIGHT.
HOWEVER...THERE WILL BE ISOLD/SCT -SHRA ALONG A COLD FRONT DROPPING
SOUTH THIS EVENING AND AGAIN AS THE FRONT GOES BACK TO THE NORTH
ON MONDAY. THUNDER IS POSSIBLE ON MONDAY...ESP OVER THE WRN MTS.
BUT THAT WILL BE AFTER THE 18Z TAF PD. GUSTY WIND FROM THE SOUTH
WILL WEAKEN AS THE NEBULOUS FRONT WASHES OUT THIS EVENING. LIGHT
WIND ON MONDAY AS THE FRONT TAKES A WHILE TO GO BACK NORTH.
.OUTLOOK...
TUE-WED...MAINLY VFR. ISOLD SHRA POSS.
THU-FRI...CFROPA. MVFR/IFR POSS IN TS/SHRA.
&&
.FIRE WEATHER...
SOUTH TO SW WINDS WILL GUST TO AROUND 20 MPH THIS EVENING BEFORE
DIMINISHING...THEN SHIFTING TO THE WNW AT AROUND 10 MPH FROM NW TO
SE OVERNIGHT. THE DRY FUELS...AND RH IN THE 35-40 PERCENT RANGE WILL
COMBINE WITH THE WIND TO CREATE A SLIGHTLY ELEVATED CHC FOR WILDFIRE
SPREAD THIS EVENING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/DANGELO
LONG TERM...MARTIN/STEINBUGL
AVIATION...DANGELO
FIRE WEATHER...LAMBERT
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
903 PM CDT SUN APR 7 2013
.UPDATE...
CURRENTLY WATCHING THE CONVECTION ACROSS THE CENTRAL PLAINS AS
THIS WILL BE MOVING UP INTO OUR AREA ON MONDAY. THE NAM AND THE
LATEST HRRR ARE FAIRLY CONSISTENT AND BRING A QUICK HITTING ROUND
OF RAIN UP HERE DURING THE MORNING. THE CURRENT FORECAST LOOKS
GOOD. THE HRRR PRECIP FIELDS SHOW A CIRCULATION THAT WILL LIKELY
BE A RESIDUAL MESO CONVECTIVE VORTEX TIED TO AN IDENTIFIABLE H5
SHORT WAVE THAT ROLLS INTO NORTHERN ILLINOIS...AND THROUGH
EXTRAPOLATION...INTO SOUTHEAST WISCONSIN.
AS MENTIONED...CURRENT FORECAST LOOKS IN GOOD SHAPE.
&&
.AVIATION/06Z TAFS/...
EXPECT CIGS/VSBYS TO DROP RAPIDLY TO MVFR FROM WEST TO EAST ACROSS
SOUTHERN WISCONSIN AROUND THE 12Z MON TIME FRAME. AREAS IN THE
SOUTHEAST WILL LIKELY SEE IFR CIGS FOR A TIME DURING MID TO LATE
MORNING. THE RAIN SHOULD MOVE OUT BY 17-18Z MONDAY WITH SOME DRIER
AIR LIFTING CIGS A BIT...BUT STILL MVFR LIKELY THROUGH THE
REMAINDER OF THE PERIOD. THERE IS A SLIGHT CHANCE FOR SOME
THUNDERSTORMS AS WELL.
&&
.PREV DISCUSSION... /ISSUED 330 PM CDT SUN APR 7 2013/
SHORT TERM...
TONIGHT AND MONDAY...FORECAST CONFIDENCE HIGH
WILL BE QUIET THIS EVENING AND THROUGH MUCH OF THE NIGHT. CLOUDS
WILL LIKELY INCREASE THROUGH THE NIGHT AHEAD OF AN APPROACHING
SHORTWAVE. RAIN SHOWERS ARE THEN EXPECTED TO MOVE INTO THE SOUTHWEST
BY DAYBREAK...SPREADING ACROSS SOUTHERN WISCONSIN THROUGH THE
MORNING HOURS. STRONGEST FORCING AND THUS BEST CHANCE FOR MODERATE
RAIN WILL BE IN THE SOUTHEAST HALF OF THE FORECAST. STILL SEEING A
LITTLE INSTABILITY IN THE SOUNDINGS...SO KEPT MENTION OF THUNDER.
INCREASING CLOUDS AND WARM ADVECTION ALOFT SHOULD KEEP TEMPS FROM
FALLING TOO FAR TONIGHT...ESPECIALLY IN THE SOUTHWEST. WILL BE QUITE
A SPREAD IN HIGH TEMPS MONDAY...WITH THE SOUTHWEST TAPPING INTO THE
MILDER AIRMASS...WHILE THE NORTHEAST REMAINS STRONGLY INFLUENCE BY
LAKE MICHIGAN.
MONDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
MODELS CONTINUE TO COME INTO MUCH BETTER AGREEMENT ON A POLAR
TROUGH AND CYCLOGENESIS THAT WILL MOVE FROM THE SRN HIGH PLAINS TO
THE LOWER GREAT LAKES THROUGH THU. LOW PRESSURE WILL DEVELOP NEAR
THE OK PANHANDLE MON NT AND BECOME AN OPEN N-S SFC TROUGH ON TUE
THAT WILL TRACK NEWD INTO THE ERN PLAINS. THE LOW WILL THEN SLOWLY
TRACK ACROSS NRN IL THROUGH WED AND THROUGH THE LOWER GREAT LAKES
ON THU. A STRONG STATIONARY FRONT WILL EXTEND FROM THE LOW...EWD ACROSS
SRN IA AND NRN IL DURING THIS PERIOD WITH REPEATED ROUNDS OF MDT
RAINFALL OVER THE REGION VIA LOW TO MID LEVEL WARM ADVECTION/FRONTOGENESIS
WITHIN AN AIRMASS OF PWS OVER ONE INCH. ENELY WINDS WILL MAKE FOR
WELL BELOW NORMAL TEMPS WHILE MARGINAL ELEVATED CAPE WILL AT LEAST
BRING SMALL CHANCES OF THUNDERSTORMS. THERMAL FIELDS TO COOL
ENOUGH WED NT TO SEE A TRANSITION TO LIGHT SNOW WITH GOOD CHANCES
OF LIGHT SNOW CONTINUING ON THU WITH THE UPPER TROUGH PASSAGE.
TOTAL QPF VALUES FOR THE WEEK WILL RANGE FROM 1-2 INCHES WITH MANY
RIVERS LIKELY REACHING BANKFULL STAGE AND SOME REACHING MINOR
FLOODING.
LONG TERM...
FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM
EXTENDED MODELS DEPICT POLAR HIGH PRESSURE SETTLING OVER THE REGION
FRI AND SAT. WITH POSSIBLY LINGERING STRATUS AND 1000-500 MB
THICKNESSES OF ONLY 534 TO 540 DM...BELOW NORMAL TEMPS WILL
CONTINUE. SLY WINDS AND WARM ADVECTION TO RETURN ON SUN IN
RESPONSE TO CYCLOGENESIS OVER THE NRN OR CENTRAL PLAINS. THIS WILL
ALSO BRING RAIN CHANCES TO THE REGION.
AVIATION/00Z TAFS/...
A SMALL AREA OF MVFR CIGS STILL HOLDING ON IN THE NORTHEAST...BUT
SHOULD DIMINISH THROUGH LATE AFTERNOON. SHOULD BE FAIRLY QUIET THEN
INTO TONIGHT. WILL LIKELY SEE A RETURN OF RAIN LATE TONIGHT OR EARLY
MONDAY MORNING...EXITING THE AREA IN THE AFTERNOON. A LITTLE THUNDER
IS ONCE AGAIN POSSIBLE. EXPECTING LOWER CIGS AS THIS SYSTEM MOVES
THROUGH.
MARINE...
PERSISTENT EASTERLY WINDS MAY BUILD WAVES TO NEAR 4 FEET BY MONDAY
AFTERNOON...THOUGH LOOKS TOO MARGINAL AT THIS POINT FOR A SMALL
CRAFT ADVISORY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/MONDAY AND AVIATION/MARINE...DDV
MONDAY NIGHT THROUGH SUNDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1226 PM CDT SAT APR 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT SAT APR 6 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A SEMI-ZONAL FLOW ACROSS THE U.S.. WITHIN THIS FLOW...WEAK
RIDGING WAS PRESENT OVER THE NORTHERN ROCKIES AS WELL AS OVER THE
FORECAST AREA...WITH A SHORTWAVE TROUGH IN-BETWEEN OVER THE WESTERN
DAKOTAS. LOW LEVEL SOUTHERLY FLOW AHEAD OF THE SHORTWAVE TROUGH...
STREAMING OUT OF THE WESTERN GULF OF MEXICO...HAS BEEN STEADILY
TRANSPORTING MOISTURE NORTHWARD. DEWPOINTS IN THE 40-50F RANGE
ENCOMPASS AN AREA FROM NEAR SIOUX FALLS SOUTH DAKOTA INTO EASTERN
TEXAS. THIS MOISTURE APPEARS MOSTLY JUST AT THE SURFACE...THOUGH...
WITH RAP 850MB DEWPOINTS GENERALLY AT OR BELOW 0C FROM THE
FORECAST AREA SOUTHWEST INTO TEXAS. WHERE THE AIR IS COOLER ACROSS
THE NORTHEAST HALF OF WISCONSIN...THE MOISTURE HAS BEEN ENOUGH TO
WORK WITH MID-LEVEL FRONTOGENESIS TO PRODUCE SNOW. OVER THE REST
OF THE FORECAST AREA...DESPITE PRESENCE OF RADAR RETURNS...MOST OF
THEM ARE ORIGINATING OUT OF 12000 FT CEILINGS AND THUS JUST VIRGA.
PLENTY OF WARM AIR ACCOMPANYING THE LOW LEVEL SOUTHERLY FLOW
TOO...WITH RAP 850MB TEMPS OF 10-15C FROM DES MOINES INTO EASTERN
SOUTH DAKOTA AND SOUTH THROUGH KANSAS. REGARDING THAT
FLOW...PROFILER AND VAD WIND DATA SHOWED SOUTHWEST WINDS OF 50-60
KT FROM THE FORECAST AREA INTO OKLAHOMA. AT THE SURFACE...LOW
PRESSURE WAS SITUATED NEAR MITCHELL SOUTH DAKOTA WITH A WARM FRONT
EXTENDING SOUTHEAST TO NEAR DES MOINES. SOUTH OF THIS
FRONT...READINGS ARE QUITE WARM...BETWEEN 55 AND 60.
A COUPLE OF ISSUES FOR THE SHORT TERM:
1. HOW WARM WILL IT GET TODAY
2. WHEN DOES PRECIPITATION DEVELOP
SHORTWAVE TROUGH SEEN OVER WESTERN SOUTH DAKOTA IS PROGGED TO MOVE
THROUGH THE FORECAST AREA THIS AFTERNOON...WITH THE ACCOMPANYING
SURFACE LOW TRACKING ALONG OR JUST NORTH OF I-90. BY 00Z...MODEL
CONSENSUS POSITION WOULD PLACE IT NEAR BLACK RIVER FALLS WI WITH ITS
COLD FRONT EXTENDING SOUTHWEST INTO FAR NORTHEAST IOWA. THIS TRACK
MEANS A DECENT PORTION OF THE FORECAST AREA...SAY SOUTHWEST OF
I-94...WILL AT LEAST FOR A TIME END UP IN THE WARM SECTOR. THUS...
THE WARM CONDITIONS SEEN YESTERDAY ACROSS NEBRASKA ARE GOING TO
ATTEMPT TO ADVECT IN. LATEST RAP TEMPERATURE FORECASTS HAVE HIGHS
ACROSS MUCH OF THE FORECAST AREA TOPPING OUT AT OR ABOVE 70. THIS
SEEMS TOO HIGH GIVEN THAT THERE WILL BE PERIODS OF MID AND HIGH
CLOUDS AS EVIDENCED ON CURRENT SATELLITE IMAGERY. STILL...THE
06.00Z NAM...REGIONAL CANADIAN AND ECMWF SUGGEST TEMPERATURES COULD
TOP OUT IN THE 60S...THUS RAISED HIGHS 5-10 DEGREES SOUTHWEST OF
I-94. IF MORE SUN OCCURS PRIOR TO THE COLD FRONTAL PASSAGE...THE
TEMPERATURES MAY NEED TO BE RAISED MORE.
THE PRECIPITATION FORECAST IS MORE PROBLEMATIC TODAY. CURRENT BAND
OF FRONTOGENETIC PRECIPITATION NORTHEAST OF I-94 WILL CONTINUE
LIFTING NORTH THIS MORNING...PERHAPS OUT OF TAYLOR COUNTY BY 12Z.
THE 06.00Z NAM/REGIONAL CANADIAN AS WELL AS RAP RUNS KEEP THE AREA
DRY AT LEAST UNTIL 18Z...WHICH SEEMS REASONABLE GIVEN THE LOW LEVEL
DRY AIR ADVECTING IN JUST ABOVE THE SURFACE ON THE LOW LEVEL JET.
HAVE IGNORED THE WETTER GFS AS SOME OF ITS QPF APPEARS TO BE
STEMMING OUT OF AN IFR DECK WHICH DOES NOT EXIST. DURING THE
AFTERNOON AS THE SHORTWAVE TROUGH MOVES IN...THERE IS GOOD MODEL
CONSENSUS OF PRECIPITATION DEVELOPING. THE PRECIPITATION THAT FORMS
NORTH OF THE SURFACE LOW TRACK WOULD BE ASSOCIATED WITH INCREASING
LOW TO MID-LEVEL DEFORMATION. TO THE SOUTH OF THE SURFACE LOW
TRACK... SUGGESTION IS MID-LEVEL COOLING ASSOCIATED WITH THE
SHORTWAVE TROUGH WILL HELP TO REMOVE THE WARM SECTOR CAPPING AND
ALLOW SOME SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP. THE CAPE IS
DEFINITELY SKINNY...ONLY A FEW HUNDRED J/KG...THUS NOT ANTICIPATING
ANYTHING SEVERE. HOWEVER...THE BREEZY LOW LEVEL JET STILL IN PLACE
ALONG WITH AN INVERTED-V SOUNDING IN PLACE FROM THE DEEP MIXING
COULD YIELD SOME GUSTS OUT OF THE SHOWERS OR THUNDERSTORMS.
HEADING INTO THE EVENING...ANOTHER SHORTWAVE CURRENTLY SEEN IN
NORTHEAST MONTANA IS PROGGED TO SLIDE THROUGH NORTHERN SECTIONS OF
THE FORECAST AREA...PHASING WITH THE SHORTWAVE TROUGH MOVING THROUGH
AT THE TIME. THE SURFACE LOW WILL DEEPEN AS A RESULT OF THIS...THUS
CAUSING TOO THE LOW TO MID LEVEL DEFORMATION ZONE ON THE
WEST-NORTHWEST SIDE OF THE SURFACE LOW TO INTENSIFY. SO THERE SHOULD
BE A PERIOD OF PRECIPITATION ACROSS MUCH OF SOUTHWEST INTO CENTRAL
WISCONSIN IN THE EVENING. ENOUGH COLD AIR MAY ACCOMPANY THE
NORTHEAST MONTANA SHORTWAVE TOO TO ALLOW THE PRECIPITATION TO CHANGE
OVER TO SNOW BRIEFLY BEFORE ENDING BY 03Z OR SO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 339 AM CDT SAT APR 6 2013
SUNDAY LOOKS TO BE THE LAST QUIET DAY BEFORE AN ACTIVE PATTERN SETS
UP FOR THE REST OF THE LONG TERM PERIOD. THIS ACTIVE PATTERN IS A
RESULT OF DEEP TROUGHING DIGGING INTO THE SOUTHWESTERN U.S. ON
MONDAY.
THE FIRST TIME PERIOD OF INTEREST IS SUNDAY NIGHT THROUGH MONDAY
MORNING. MODELS HAVE COME INTO BETTER AGREEMENT WITH ALL SHOWING A
SHORTWAVE MOVING THROUGH THE FORECAST AREA DURING THIS TIME PERIOD.
DPVA ASSOCIATED WITH THE SHORTWAVE COMBINED WITH A SURGE OF
ISENTROPIC LIFT SHOULD YIELD PRECIPITATION ACROSS MUCH OF THE
FORECAST AREA. WITH THE INCREASED MODEL CONSENSUS ON THIS SIGNAL...
HAVE RAISED PRECIPITATION CHANCES GREATLY...PARTICULARLY BETWEEN .
DOES APPEAR THAT THE BEST LOW LEVEL FRONTOGENETIC FORCING WILL END
UP JUST SOUTH OF THE FORECAST AREA...PER 06.00Z GFS/ECMWF...THUS THE
HEAVIEST QPF SHOULD STAY TO THE SOUTH. THERE ALSO COULD BE A SHOT
FOR SOME SNOW TO MIX IN NORTH OF I-94...GIVEN COOLER TEMPERATURES
THERE...BUT NO ACCUMULATIONS ARE EXPECTED.
THERE ARE SOME INDICATIONS THAT MONDAY AFTERNOON THROUGH TUESDAY
MORNING COULD BE A BRIEF DRY PERIOD...IN RESPONSE TO SUBSIDENCE
BEHIND THE SHORTWAVE. IF ENOUGH SUBSIDENCE CAN OCCUR TO SCOUR CLOUDS
OUT...850MB TEMPS HOLDING IN THE 6-8C RANGE COULD SUPPORT
TEMPERATURES CLIMBING WELL INTO THE 60S DESPITE A LIGHT LOW LEVEL
NORTHEAST FLOW...AS INDICATED BY THE 06.00Z ECMWF. ALL GUIDANCE
SUGGESTED WARMER ON MONDAY AND THUS HEADED IN THAT DIRECTION...BUT
TEMPERATURES MAY NEED TO BE BOOSTED MORE. ALSO OF INTEREST IN THE
06.00Z ECMWF IS LIGHT PRECIPITATION SHOWN FROM SOUTH DAKOTA INTO
NORTHERN WISCONSIN MONDAY AFTERNOON AND EVENING. APPEARS THIS IS DUE
TO A MID LEVEL FRONTOGENESIS ZONE. IN CASE THIS WOULD COME TO
FRUITION...HAVE MAINTAINED SOME LOW PRECIPITATION CHANCES.
FOR TUESDAY AND BEYOND...ALL FOCUS IS ON THE SOUTHWESTERN U.S.
TROUGH AND HOW AND WHEN IT EJECTS OUT. MODELS REMAIN AT ODDS...WITH
THE 06.00Z GFS/CANADIAN MORE AGGRESSIVE...BRINGING A SURFACE LOW
THROUGH THE FORECAST AREA WEDNESDAY MORNING. MEANWHILE THE 06.00Z
ECMWF CONTINUES THE IDEA OF KEEPING ANY SURFACE LOW WELL TO THE
SOUTH...CROSSING THE OHIO VALLEY AND MUCH SLOWER WITH THE EJECTION
OF THE UPPER TROUGH. EITHER SCENARIO LOOKS FAVORABLE FOR
PRECIPITATION MOVING IN FOR TUESDAY NIGHT...INDUCED BY A SURGE OF
MOISTURE TRANSPORT TOWARDS THE AREA...ALONG WITH UPPER DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF A JET OVER THE GREAT LAKES. AS A
RESULT...HAVE RAISED PRECIPITATION CHANCES MORE TO THE 60-70 RANGE.
FOLLOWED A MODEL CONSENSUS FOR WEDNESDAY THROUGH FRIDAY WHICH
REQUIRES AT LEAST SOME MENTION OF PRECIPITATION ALMOST EACH DAY
EXCEPT FRIDAY. THIS IS ALL DUE TO THE UPPER TROUGH AFFECTING THE
AREA. ADDITIONALLY...COOLER AIR MOVES IN WITH THE UPPER
TROUGH...ENOUGH THAT WE COULD DEAL WITH SOME SNOW COME WEDNESDAY
NIGHT AND THURSDAY. FOLLOWED A CONSENSUS APPROACH TOO FOR
TEMPERATURES...BUT THESE MAY NEED TO BE ADJUSTED EITHER WARMER OR
COOLER ONCE MORE CERTAINTY EXISTS ON THE PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1226 PM CDT SAT APR 6 2013
SURFACE LOW NOW OVER SOUTHWEST MINNESOTA WILL CONTINUE TO TRACK
EAST-NORTHEAST INTO WESTERN WISCONSIN BY 00Z SUNDAY. EXPECT SOUTHERLY
WINDS AHEAD OF IT WITH VFR CEILINGS. ASSOCIATED COLD FRONT WILL
PUSH THROUGH THE TAF SITES BETWEEN 22Z-00Z THIS AFTERNOON WITH A
WIND SHIFT TO THE WEST-NORTHWEST. BOTH THE 06.12Z NAM AND 06.15Z
RAP BUFKIT SOUNDINGS SHOW LOW LEVEL MOISTURE FILLING BEHIND THE
FRONT WITH THE POTENTIAL FOR LOWER MVFR CEILINGS AT BOTH TAF
SITES AND HAVE TRENDED THE FORECAST THIS WAY. A FEW SHOWERS OR
EVEN ISOLATED TSRA MAY ACCOMPANY THE FRONT. FOR NOW HAVE JUST
MENTIONED SHRA. EXPECT CEILINGS TO RISE BETWEEN 15Z-18Z SUNDAY WITH
PERHAPS SOME CLEARING BY 18Z.
&&
.HYDROLOGY...
ISSUED AT 339 AM CDT SAT APR 6 2013
RIVER STATUS...
AN ICE JAM PERSISTS ON THE BLACK RIVER ON THE NORTH SIDE OF
NEILLSVILLE. THIS ICE JAM COMBINED WITH SNOW MELT MOVING THROUGH THE
RIVER HAS RESULTED IN DIFFICULT FORECASTING DOWNSTREAM...BUT MOST OF
THE RIVER IS STILL RUNNING WITHIN BANK. THE TREMPEALEAU RIVER NEAR
DODGE REMAINS ABOVE MINOR FLOOD STAGE. ELSEWHERE...RIVERS APPEARS TO
BE STEADILY FALLING.
SNOW PACK...
THIS IS TOUGH TO SAY AS LATEST NOHRSC DATA SEEMS OVERDONE WITH THE
AMOUNT OF SNOW ON THE GROUND...COMPARED TO AT LEAST 7 AM COOP DATA
YESTERDAY. THERE MAY NOT BE MUCH SNOW LEFT ACROSS SOUTHEAST
MINNESOTA AND EVEN THE SOUTHERN PORTIONS OF BUFFALO AND TREMPEALEAU
COUNTIES. ACROSS NORTHERN PORTIONS OF THESE COUNTIES INTO TAYLOR AND
CLARK...THINKING AT LEAST 1 TO LOCALLY 4 INCHES OF WATER AMOUNT
EXISTS.
RAINFALL...
THE SYSTEM COMING THROUGH TODAY AND THIS EVENING CONTINUES TO LOOK
LESS IMPRESSIVE IN TERMS OF AMOUNTS...NOW MAYBE UP TO A 1/4 INCH.
THERE CERTAINLY COULD BE A FEW HIGHER AMOUNTS IF SOME THUNDERSTORMS
GET GOING. ANOTHER SHOT FOR RAINFALL COMES SUNDAY NIGHT INTO MONDAY
MORNING WHICH COULD TOTAL 1/4 TO 1/2 INCH. MORE RAIN IS POSSIBLE
TUESDAY THROUGH THURSDAY WITH POTENTIAL FOR MODERATE RAINFALL.
TEMPERATURES...
THERE IS BIG CONCERN TODAY FOR RAPID SNOW MELT WITH READINGS
CLIMBING INTO THE MID 40S TO MID 50S OVER THE SNOW PACK AREAS. IN
FACT...THERE IS A CHANCE SOME LOCATIONS ALONG I-94 COULD TOP OUT AT
60. MOST OF THE NEXT 7 DAYS LOOK TO HAVE DAYTIME TEMPERATURES AT
LEAST 40 FOR CONTINUED FAVORABLE SNOW MELT CONDITIONS.
FROST DEPTH...
NO RECENT REPORTS ARE AVAILABLE. AS OF APRIL 4TH...FROST DEPTHS
ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1 1/2 FEET
SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH CENTRAL
WISCONSIN. THIS FROST WILL CAUSE MUCH OF THE RUNOFF FROM SNOW MELT
RUNOFF AND PRECIPITATION TO GO INTO STREAMS AND RIVERS.
SUMMARY...
MAIN CONCERN FOR FLOODING TODAY COMES FROM SNOW PACK MELTING...DUE
TO THE WARM AIR MOVING IN...WHICH A BREEZY SOUTH WIND AND DEWPOINTS
NEAR 40 WILL AID EVEN MORE IN THE MELTING PROCESS. THE ONLY ITEMS
PRECLUDING A FLOOD WATCH RIGHT NOW IS UNCERTAINTY ON THE AMOUNT OF
SNOW AND WATER EQUIVALENT...ALONG WITH THE FACT THAT THE TREMPEALEAU
RIVER AT DODGE ALREADY HAS A FLOOD WARNING. AS WE HEAD THROUGH THE
NEXT COUPLE OF DAYS...THE AMOUNT OF SNOW AND WATER EQUIVALENT
AVAILABLE WILL BECOME EVEN MORE PROBLEMATIC. ALREADY IT APPEARS THE
FLOODING POTENTIAL FROM SNOW PACK MELTING HAS MOSTLY ENDED FOR MUCH
OF SOUTHEAST MINNESOTA...SEEING THAT THE WHITEWATER RIVER DID NOT
RISE NEARLY AS MUCH YESTERDAY. OVERALL...THE BIGGEST FLOODING
CONCERNS ARE THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
653 AM CDT SAT APR 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT SAT APR 6 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A SEMI-ZONAL FLOW ACROSS THE U.S.. WITHIN THIS FLOW...WEAK
RIDGING WAS PRESENT OVER THE NORTHERN ROCKIES AS WELL AS OVER THE
FORECAST AREA...WITH A SHORTWAVE TROUGH IN-BETWEEN OVER THE WESTERN
DAKOTAS. LOW LEVEL SOUTHERLY FLOW AHEAD OF THE SHORTWAVE TROUGH...
STREAMING OUT OF THE WESTERN GULF OF MEXICO...HAS BEEN STEADILY
TRANSPORTING MOISTURE NORTHWARD. DEWPOINTS IN THE 40-50F RANGE
ENCOMPASS AN AREA FROM NEAR SIOUX FALLS SOUTH DAKOTA INTO EASTERN
TEXAS. THIS MOISTURE APPEARS MOSTLY JUST AT THE SURFACE...THOUGH...
WITH RAP 850MB DEWPOINTS GENERALLY AT OR BELOW 0C FROM THE
FORECAST AREA SOUTHWEST INTO TEXAS. WHERE THE AIR IS COOLER ACROSS
THE NORTHEAST HALF OF WISCONSIN...THE MOISTURE HAS BEEN ENOUGH TO
WORK WITH MID-LEVEL FRONTOGENESIS TO PRODUCE SNOW. OVER THE REST
OF THE FORECAST AREA...DESPITE PRESENCE OF RADAR RETURNS...MOST OF
THEM ARE ORIGINATING OUT OF 12000 FT CEILINGS AND THUS JUST VIRGA.
PLENTY OF WARM AIR ACCOMPANYING THE LOW LEVEL SOUTHERLY FLOW
TOO...WITH RAP 850MB TEMPS OF 10-15C FROM DES MOINES INTO EASTERN
SOUTH DAKOTA AND SOUTH THROUGH KANSAS. REGARDING THAT
FLOW...PROFILER AND VAD WIND DATA SHOWED SOUTHWEST WINDS OF 50-60
KT FROM THE FORECAST AREA INTO OKLAHOMA. AT THE SURFACE...LOW
PRESSURE WAS SITUATED NEAR MITCHELL SOUTH DAKOTA WITH A WARM FRONT
EXTENDING SOUTHEAST TO NEAR DES MOINES. SOUTH OF THIS
FRONT...READINGS ARE QUITE WARM...BETWEEN 55 AND 60.
A COUPLE OF ISSUES FOR THE SHORT TERM:
1. HOW WARM WILL IT GET TODAY
2. WHEN DOES PRECIPITATION DEVELOP
SHORTWAVE TROUGH SEEN OVER WESTERN SOUTH DAKOTA IS PROGGED TO MOVE
THROUGH THE FORECAST AREA THIS AFTERNOON...WITH THE ACCOMPANYING
SURFACE LOW TRACKING ALONG OR JUST NORTH OF I-90. BY 00Z...MODEL
CONSENSUS POSITION WOULD PLACE IT NEAR BLACK RIVER FALLS WI WITH ITS
COLD FRONT EXTENDING SOUTHWEST INTO FAR NORTHEAST IOWA. THIS TRACK
MEANS A DECENT PORTION OF THE FORECAST AREA...SAY SOUTHWEST OF
I-94...WILL AT LEAST FOR A TIME END UP IN THE WARM SECTOR. THUS...
THE WARM CONDITIONS SEEN YESTERDAY ACROSS NEBRASKA ARE GOING TO
ATTEMPT TO ADVECT IN. LATEST RAP TEMPERATURE FORECASTS HAVE HIGHS
ACROSS MUCH OF THE FORECAST AREA TOPPING OUT AT OR ABOVE 70. THIS
SEEMS TOO HIGH GIVEN THAT THERE WILL BE PERIODS OF MID AND HIGH
CLOUDS AS EVIDENCED ON CURRENT SATELLITE IMAGERY. STILL...THE
06.00Z NAM...REGIONAL CANADIAN AND ECMWF SUGGEST TEMPERATURES COULD
TOP OUT IN THE 60S...THUS RAISED HIGHS 5-10 DEGREES SOUTHWEST OF
I-94. IF MORE SUN OCCURS PRIOR TO THE COLD FRONTAL PASSAGE...THE
TEMPERATURES MAY NEED TO BE RAISED MORE.
THE PRECIPITATION FORECAST IS MORE PROBLEMATIC TODAY. CURRENT BAND
OF FRONTOGENETIC PRECIPITATION NORTHEAST OF I-94 WILL CONTINUE
LIFTING NORTH THIS MORNING...PERHAPS OUT OF TAYLOR COUNTY BY 12Z.
THE 06.00Z NAM/REGIONAL CANADIAN AS WELL AS RAP RUNS KEEP THE AREA
DRY AT LEAST UNTIL 18Z...WHICH SEEMS REASONABLE GIVEN THE LOW LEVEL
DRY AIR ADVECTING IN JUST ABOVE THE SURFACE ON THE LOW LEVEL JET.
HAVE IGNORED THE WETTER GFS AS SOME OF ITS QPF APPEARS TO BE
STEMMING OUT OF AN IFR DECK WHICH DOES NOT EXIST. DURING THE
AFTERNOON AS THE SHORTWAVE TROUGH MOVES IN...THERE IS GOOD MODEL
CONSENSUS OF PRECIPITATION DEVELOPING. THE PRECIPITATION THAT FORMS
NORTH OF THE SURFACE LOW TRACK WOULD BE ASSOCIATED WITH INCREASING
LOW TO MID-LEVEL DEFORMATION. TO THE SOUTH OF THE SURFACE LOW
TRACK... SUGGESTION IS MID-LEVEL COOLING ASSOCIATED WITH THE
SHORTWAVE TROUGH WILL HELP TO REMOVE THE WARM SECTOR CAPPING AND
ALLOW SOME SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP. THE CAPE IS
DEFINITELY SKINNY...ONLY A FEW HUNDRED J/KG...THUS NOT ANTICIPATING
ANYTHING SEVERE. HOWEVER...THE BREEZY LOW LEVEL JET STILL IN PLACE
ALONG WITH AN INVERTED-V SOUNDING IN PLACE FROM THE DEEP MIXING
COULD YIELD SOME GUSTS OUT OF THE SHOWERS OR THUNDERSTORMS.
HEADING INTO THE EVENING...ANOTHER SHORTWAVE CURRENTLY SEEN IN
NORTHEAST MONTANA IS PROGGED TO SLIDE THROUGH NORTHERN SECTIONS OF
THE FORECAST AREA...PHASING WITH THE SHORTWAVE TROUGH MOVING THROUGH
AT THE TIME. THE SURFACE LOW WILL DEEPEN AS A RESULT OF THIS...THUS
CAUSING TOO THE LOW TO MID LEVEL DEFORMATION ZONE ON THE
WEST-NORTHWEST SIDE OF THE SURFACE LOW TO INTENSIFY. SO THERE SHOULD
BE A PERIOD OF PRECIPITATION ACROSS MUCH OF SOUTHWEST INTO CENTRAL
WISCONSIN IN THE EVENING. ENOUGH COLD AIR MAY ACCOMPANY THE
NORTHEAST MONTANA SHORTWAVE TOO TO ALLOW THE PRECIPITATION TO CHANGE
OVER TO SNOW BRIEFLY BEFORE ENDING BY 03Z OR SO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 339 AM CDT SAT APR 6 2013
SUNDAY LOOKS TO BE THE LAST QUIET DAY BEFORE AN ACTIVE PATTERN SETS
UP FOR THE REST OF THE LONG TERM PERIOD. THIS ACTIVE PATTERN IS A
RESULT OF DEEP TROUGHING DIGGING INTO THE SOUTHWESTERN U.S. ON
MONDAY.
THE FIRST TIME PERIOD OF INTEREST IS SUNDAY NIGHT THROUGH MONDAY
MORNING. MODELS HAVE COME INTO BETTER AGREEMENT WITH ALL SHOWING A
SHORTWAVE MOVING THROUGH THE FORECAST AREA DURING THIS TIME PERIOD.
DPVA ASSOCIATED WITH THE SHORTWAVE COMBINED WITH A SURGE OF
ISENTROPIC LIFT SHOULD YIELD PRECIPITATION ACROSS MUCH OF THE
FORECAST AREA. WITH THE INCREASED MODEL CONSENSUS ON THIS SIGNAL...
HAVE RAISED PRECIPITATION CHANCES GREATLY...PARTICULARLY BETWEEN .
DOES APPEAR THAT THE BEST LOW LEVEL FRONTOGENETIC FORCING WILL END
UP JUST SOUTH OF THE FORECAST AREA...PER 06.00Z GFS/ECMWF...THUS THE
HEAVIEST QPF SHOULD STAY TO THE SOUTH. THERE ALSO COULD BE A SHOT
FOR SOME SNOW TO MIX IN NORTH OF I-94...GIVEN COOLER TEMPERATURES
THERE...BUT NO ACCUMULATIONS ARE EXPECTED.
THERE ARE SOME INDICATIONS THAT MONDAY AFTERNOON THROUGH TUESDAY
MORNING COULD BE A BRIEF DRY PERIOD...IN RESPONSE TO SUBSIDENCE
BEHIND THE SHORTWAVE. IF ENOUGH SUBSIDENCE CAN OCCUR TO SCOUR CLOUDS
OUT...850MB TEMPS HOLDING IN THE 6-8C RANGE COULD SUPPORT
TEMPERATURES CLIMBING WELL INTO THE 60S DESPITE A LIGHT LOW LEVEL
NORTHEAST FLOW...AS INDICATED BY THE 06.00Z ECMWF. ALL GUIDANCE
SUGGESTED WARMER ON MONDAY AND THUS HEADED IN THAT DIRECTION...BUT
TEMPERATURES MAY NEED TO BE BOOSTED MORE. ALSO OF INTEREST IN THE
06.00Z ECMWF IS LIGHT PRECIPITATION SHOWN FROM SOUTH DAKOTA INTO
NORTHERN WISCONSIN MONDAY AFTERNOON AND EVENING. APPEARS THIS IS DUE
TO A MID LEVEL FRONTOGENESIS ZONE. IN CASE THIS WOULD COME TO
FRUITION...HAVE MAINTAINED SOME LOW PRECIPITATION CHANCES.
FOR TUESDAY AND BEYOND...ALL FOCUS IS ON THE SOUTHWESTERN U.S.
TROUGH AND HOW AND WHEN IT EJECTS OUT. MODELS REMAIN AT ODDS...WITH
THE 06.00Z GFS/CANADIAN MORE AGGRESSIVE...BRINGING A SURFACE LOW
THROUGH THE FORECAST AREA WEDNESDAY MORNING. MEANWHILE THE 06.00Z
ECMWF CONTINUES THE IDEA OF KEEPING ANY SURFACE LOW WELL TO THE
SOUTH...CROSSING THE OHIO VALLEY AND MUCH SLOWER WITH THE EJECTION
OF THE UPPER TROUGH. EITHER SCENARIO LOOKS FAVORABLE FOR
PRECIPITATION MOVING IN FOR TUESDAY NIGHT...INDUCED BY A SURGE OF
MOISTURE TRANSPORT TOWARDS THE AREA...ALONG WITH UPPER DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF A JET OVER THE GREAT LAKES. AS A
RESULT...HAVE RAISED PRECIPITATION CHANCES MORE TO THE 60-70 RANGE.
FOLLOWED A MODEL CONSENSUS FOR WEDNESDAY THROUGH FRIDAY WHICH
REQUIRES AT LEAST SOME MENTION OF PRECIPITATION ALMOST EACH DAY
EXCEPT FRIDAY. THIS IS ALL DUE TO THE UPPER TROUGH AFFECTING THE
AREA. ADDITIONALLY...COOLER AIR MOVES IN WITH THE UPPER
TROUGH...ENOUGH THAT WE COULD DEAL WITH SOME SNOW COME WEDNESDAY
NIGHT AND THURSDAY. FOLLOWED A CONSENSUS APPROACH TOO FOR
TEMPERATURES...BUT THESE MAY NEED TO BE ADJUSTED EITHER WARMER OR
COOLER ONCE MORE CERTAINTY EXISTS ON THE PRECIPITATION.
&&
.AVIATION...TODAY AND TONIGHT
650 AM CDT SAT APR 6 2013
AS THE LOW LEVEL JET DISSIPATES THIS MORNING...THE LOW LEVEL WIND
SHEAR WILL COME TO AN END AT LA CROSSE BY 06.16Z. MEANWHILE THE
SOUNDINGS CONTINUE TO SHOW THAT THE LOW LEVELS WILL REMAIN WELL
MIXED AT KRST...THUS EXPECT WINDS TO GUST UP TO 30 KNOTS THROUGH
06.22Z. CEILINGS THIS MORNING WILL BE AT OR ABOVE 12K FEET.
AS THE COLD FRONT APPROACHES THE AREA THIS AFTERNOON...EXPECT
SHOWERS TO DEVELOP AT KRST AROUND 06.18Z AND AT KLSE AROUND
06.20Z. THERE MAY BE EVEN AN ISOLATED THUNDERSTORM...BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF FORECAST.
CEILINGS WILL LOWER INTO THE 4-6K FEET AHEAD OF THIS COLD
FRONT...AND THEN BECOME IFR TO MVFR IN THE WAKE OF THE FRONT.
WINDS WILL SHIFT FROM SOUTHWEST TO NORTHWEST BEHIND THE FRONT AND
THE WIND SPEEDS WILL GRADUALLY SUBSIDE THROUGH THE REMAINDER OF
THE NIGHT.
&&
.HYDROLOGY...
ISSUED AT 339 AM CDT SAT APR 6 2013
RIVER STATUS...
AN ICE JAM PERSISTS ON THE BLACK RIVER ON THE NORTH SIDE OF
NEILLSVILLE. THIS ICE JAM COMBINED WITH SNOW MELT MOVING THROUGH THE
RIVER HAS RESULTED IN DIFFICULT FORECASTING DOWNSTREAM...BUT MOST OF
THE RIVER IS STILL RUNNING WITHIN BANK. THE TREMPEALEAU RIVER NEAR
DODGE REMAINS ABOVE MINOR FLOOD STAGE. ELSEWHERE...RIVERS APPEARS TO
BE STEADILY FALLING.
SNOW PACK...
THIS IS TOUGH TO SAY AS LATEST NOHRSC DATA SEEMS OVERDONE WITH THE
AMOUNT OF SNOW ON THE GROUND...COMPARED TO AT LEAST 7 AM COOP DATA
YESTERDAY. THERE MAY NOT BE MUCH SNOW LEFT ACROSS SOUTHEAST
MINNESOTA AND EVEN THE SOUTHERN PORTIONS OF BUFFALO AND TREMPEALEAU
COUNTIES. ACROSS NORTHERN PORTIONS OF THESE COUNTIES INTO TAYLOR AND
CLARK...THINKING AT LEAST 1 TO LOCALLY 4 INCHES OF WATER AMOUNT
EXISTS.
RAINFALL...
THE SYSTEM COMING THROUGH TODAY AND THIS EVENING CONTINUES TO LOOK
LESS IMPRESSIVE IN TERMS OF AMOUNTS...NOW MAYBE UP TO A 1/4 INCH.
THERE CERTAINLY COULD BE A FEW HIGHER AMOUNTS IF SOME THUNDERSTORMS
GET GOING. ANOTHER SHOT FOR RAINFALL COMES SUNDAY NIGHT INTO MONDAY
MORNING WHICH COULD TOTAL 1/4 TO 1/2 INCH. MORE RAIN IS POSSIBLE
TUESDAY THROUGH THURSDAY WITH POTENTIAL FOR MODERATE RAINFALL.
TEMPERATURES...
THERE IS BIG CONCERN TODAY FOR RAPID SNOW MELT WITH READINGS
CLIMBING INTO THE MID 40S TO MID 50S OVER THE SNOW PACK AREAS. IN
FACT...THERE IS A CHANCE SOME LOCATIONS ALONG I-94 COULD TOP OUT AT
60. MOST OF THE NEXT 7 DAYS LOOK TO HAVE DAYTIME TEMPERATURES AT
LEAST 40 FOR CONTINUED FAVORABLE SNOW MELT CONDITIONS.
FROST DEPTH...
NO RECENT REPORTS ARE AVAILABLE. AS OF APRIL 4TH...FROST DEPTHS
ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1 1/2 FEET
SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH CENTRAL
WISCONSIN. THIS FROST WILL CAUSE MUCH OF THE RUNOFF FROM SNOW MELT
RUNOFF AND PRECIPITATION TO GO INTO STREAMS AND RIVERS.
SUMMARY...
MAIN CONCERN FOR FLOODING TODAY COMES FROM SNOW PACK MELTING...DUE
TO THE WARM AIR MOVING IN...WHICH A BREEZY SOUTH WIND AND DEWPOINTS
NEAR 40 WILL AID EVEN MORE IN THE MELTING PROCESS. THE ONLY ITEMS
PRECLUDING A FLOOD WATCH RIGHT NOW IS UNCERTAINTY ON THE AMOUNT OF
SNOW AND WATER EQUIVALENT...ALONG WITH THE FACT THAT THE TREMPEALEAU
RIVER AT DODGE ALREADY HAS A FLOOD WARNING. AS WE HEAD THROUGH THE
NEXT COUPLE OF DAYS...THE AMOUNT OF SNOW AND WATER EQUIVALENT
AVAILABLE WILL BECOME EVEN MORE PROBLEMATIC. ALREADY IT APPEARS THE
FLOODING POTENTIAL FROM SNOW PACK MELTING HAS MOSTLY ENDED FOR MUCH
OF SOUTHEAST MINNESOTA...SEEING THAT THE WHITEWATER RIVER DID NOT
RISE NEARLY AS MUCH YESTERDAY. OVERALL...THE BIGGEST FLOODING
CONCERNS ARE THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
339 AM CDT SAT APR 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT SAT APR 6 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A SEMI-ZONAL FLOW ACROSS THE U.S.. WITHIN THIS FLOW...WEAK
RIDGING WAS PRESENT OVER THE NORTHERN ROCKIES AS WELL AS OVER THE
FORECAST AREA...WITH A SHORTWAVE TROUGH IN-BETWEEN OVER THE WESTERN
DAKOTAS. LOW LEVEL SOUTHERLY FLOW AHEAD OF THE SHORTWAVE TROUGH...
STREAMING OUT OF THE WESTERN GULF OF MEXICO...HAS BEEN STEADILY
TRANSPORTING MOISTURE NORTHWARD. DEWPOINTS IN THE 40-50F RANGE
ENCOMPASS AN AREA FROM NEAR SIOUX FALLS SOUTH DAKOTA INTO EASTERN
TEXAS. THIS MOISTURE APPEARS MOSTLY JUST AT THE SURFACE...THOUGH...
WITH RAP 850MB DEWPOINTS GENERALLY AT OR BELOW 0C FROM THE
FORECAST AREA SOUTHWEST INTO TEXAS. WHERE THE AIR IS COOLER ACROSS
THE NORTHEAST HALF OF WISCONSIN...THE MOISTURE HAS BEEN ENOUGH TO
WORK WITH MID-LEVEL FRONTOGENESIS TO PRODUCE SNOW. OVER THE REST
OF THE FORECAST AREA...DESPITE PRESENCE OF RADAR RETURNS...MOST OF
THEM ARE ORIGINATING OUT OF 12000 FT CEILINGS AND THUS JUST VIRGA.
PLENTY OF WARM AIR ACCOMPANYING THE LOW LEVEL SOUTHERLY FLOW
TOO...WITH RAP 850MB TEMPS OF 10-15C FROM DES MOINES INTO EASTERN
SOUTH DAKOTA AND SOUTH THROUGH KANSAS. REGARDING THAT
FLOW...PROFILER AND VAD WIND DATA SHOWED SOUTHWEST WINDS OF 50-60
KT FROM THE FORECAST AREA INTO OKLAHOMA. AT THE SURFACE...LOW
PRESSURE WAS SITUATED NEAR MITCHELL SOUTH DAKOTA WITH A WARM FRONT
EXTENDING SOUTHEAST TO NEAR DES MOINES. SOUTH OF THIS
FRONT...READINGS ARE QUITE WARM...BETWEEN 55 AND 60.
A COUPLE OF ISSUES FOR THE SHORT TERM:
1. HOW WARM WILL IT GET TODAY
2. WHEN DOES PRECIPITATION DEVELOP
SHORTWAVE TROUGH SEEN OVER WESTERN SOUTH DAKOTA IS PROGGED TO MOVE
THROUGH THE FORECAST AREA THIS AFTERNOON...WITH THE ACCOMPANYING
SURFACE LOW TRACKING ALONG OR JUST NORTH OF I-90. BY 00Z...MODEL
CONSENSUS POSITION WOULD PLACE IT NEAR BLACK RIVER FALLS WI WITH ITS
COLD FRONT EXTENDING SOUTHWEST INTO FAR NORTHEAST IOWA. THIS TRACK
MEANS A DECENT PORTION OF THE FORECAST AREA...SAY SOUTHWEST OF
I-94...WILL AT LEAST FOR A TIME END UP IN THE WARM SECTOR. THUS...
THE WARM CONDITIONS SEEN YESTERDAY ACROSS NEBRASKA ARE GOING TO
ATTEMPT TO ADVECT IN. LATEST RAP TEMPERATURE FORECASTS HAVE HIGHS
ACROSS MUCH OF THE FORECAST AREA TOPPING OUT AT OR ABOVE 70. THIS
SEEMS TOO HIGH GIVEN THAT THERE WILL BE PERIODS OF MID AND HIGH
CLOUDS AS EVIDENCED ON CURRENT SATELLITE IMAGERY. STILL...THE
06.00Z NAM...REGIONAL CANADIAN AND ECMWF SUGGEST TEMPERATURES COULD
TOP OUT IN THE 60S...THUS RAISED HIGHS 5-10 DEGREES SOUTHWEST OF
I-94. IF MORE SUN OCCURS PRIOR TO THE COLD FRONTAL PASSAGE...THE
TEMPERATURES MAY NEED TO BE RAISED MORE.
THE PRECIPITATION FORECAST IS MORE PROBLEMATIC TODAY. CURRENT BAND
OF FRONTOGENETIC PRECIPITATION NORTHEAST OF I-94 WILL CONTINUE
LIFTING NORTH THIS MORNING...PERHAPS OUT OF TAYLOR COUNTY BY 12Z.
THE 06.00Z NAM/REGIONAL CANADIAN AS WELL AS RAP RUNS KEEP THE AREA
DRY AT LEAST UNTIL 18Z...WHICH SEEMS REASONABLE GIVEN THE LOW LEVEL
DRY AIR ADVECTING IN JUST ABOVE THE SURFACE ON THE LOW LEVEL JET.
HAVE IGNORED THE WETTER GFS AS SOME OF ITS QPF APPEARS TO BE
STEMMING OUT OF AN IFR DECK WHICH DOES NOT EXIST. DURING THE
AFTERNOON AS THE SHORTWAVE TROUGH MOVES IN...THERE IS GOOD MODEL
CONSENSUS OF PRECIPITATION DEVELOPING. THE PRECIPITATION THAT FORMS
NORTH OF THE SURFACE LOW TRACK WOULD BE ASSOCIATED WITH INCREASING
LOW TO MID-LEVEL DEFORMATION. TO THE SOUTH OF THE SURFACE LOW
TRACK... SUGGESTION IS MID-LEVEL COOLING ASSOCIATED WITH THE
SHORTWAVE TROUGH WILL HELP TO REMOVE THE WARM SECTOR CAPPING AND
ALLOW SOME SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP. THE CAPE IS
DEFINITELY SKINNY...ONLY A FEW HUNDRED J/KG...THUS NOT ANTICIPATING
ANYTHING SEVERE. HOWEVER...THE BREEZY LOW LEVEL JET STILL IN PLACE
ALONG WITH AN INVERTED-V SOUNDING IN PLACE FROM THE DEEP MIXING
COULD YIELD SOME GUSTS OUT OF THE SHOWERS OR THUNDERSTORMS.
HEADING INTO THE EVENING...ANOTHER SHORTWAVE CURRENTLY SEEN IN
NORTHEAST MONTANA IS PROGGED TO SLIDE THROUGH NORTHERN SECTIONS OF
THE FORECAST AREA...PHASING WITH THE SHORTWAVE TROUGH MOVING THROUGH
AT THE TIME. THE SURFACE LOW WILL DEEPEN AS A RESULT OF THIS...THUS
CAUSING TOO THE LOW TO MID LEVEL DEFORMATION ZONE ON THE
WEST-NORTHWEST SIDE OF THE SURFACE LOW TO INTENSIFY. SO THERE SHOULD
BE A PERIOD OF PRECIPITATION ACROSS MUCH OF SOUTHWEST INTO CENTRAL
WISCONSIN IN THE EVENING. ENOUGH COLD AIR MAY ACCOMPANY THE
NORTHEAST MONTANA SHORTWAVE TOO TO ALLOW THE PRECIPITATION TO CHANGE
OVER TO SNOW BRIEFLY BEFORE ENDING BY 03Z OR SO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 339 AM CDT SAT APR 6 2013
SUNDAY LOOKS TO BE THE LAST QUIET DAY BEFORE AN ACTIVE PATTERN SETS
UP FOR THE REST OF THE LONG TERM PERIOD. THIS ACTIVE PATTERN IS A
RESULT OF DEEP TROUGHING DIGGING INTO THE SOUTHWESTERN U.S. ON
MONDAY.
THE FIRST TIME PERIOD OF INTEREST IS SUNDAY NIGHT THROUGH MONDAY
MORNING. MODELS HAVE COME INTO BETTER AGREEMENT WITH ALL SHOWING A
SHORTWAVE MOVING THROUGH THE FORECAST AREA DURING THIS TIME PERIOD.
DPVA ASSOCIATED WITH THE SHORTWAVE COMBINED WITH A SURGE OF
ISENTROPIC LIFT SHOULD YIELD PRECIPITATION ACROSS MUCH OF THE
FORECAST AREA. WITH THE INCREASED MODEL CONSENSUS ON THIS SIGNAL...
HAVE RAISED PRECIPITATION CHANCES GREATLY...PARTICULARLY BETWEEN .
DOES APPEAR THAT THE BEST LOW LEVEL FRONTOGENETIC FORCING WILL END
UP JUST SOUTH OF THE FORECAST AREA...PER 06.00Z GFS/ECMWF...THUS THE
HEAVIEST QPF SHOULD STAY TO THE SOUTH. THERE ALSO COULD BE A SHOT
FOR SOME SNOW TO MIX IN NORTH OF I-94...GIVEN COOLER TEMPERATURES
THERE...BUT NO ACCUMULATIONS ARE EXPECTED.
THERE ARE SOME INDICATIONS THAT MONDAY AFTERNOON THROUGH TUESDAY
MORNING COULD BE A BRIEF DRY PERIOD...IN RESPONSE TO SUBSIDENCE
BEHIND THE SHORTWAVE. IF ENOUGH SUBSIDENCE CAN OCCUR TO SCOUR CLOUDS
OUT...850MB TEMPS HOLDING IN THE 6-8C RANGE COULD SUPPORT
TEMPERATURES CLIMBING WELL INTO THE 60S DESPITE A LIGHT LOW LEVEL
NORTHEAST FLOW...AS INDICATED BY THE 06.00Z ECMWF. ALL GUIDANCE
SUGGESTED WARMER ON MONDAY AND THUS HEADED IN THAT DIRECTION...BUT
TEMPERATURES MAY NEED TO BE BOOSTED MORE. ALSO OF INTEREST IN THE
06.00Z ECMWF IS LIGHT PRECIPITATION SHOWN FROM SOUTH DAKOTA INTO
NORTHERN WISCONSIN MONDAY AFTERNOON AND EVENING. APPEARS THIS IS DUE
TO A MID LEVEL FRONTOGENESIS ZONE. IN CASE THIS WOULD COME TO
FRUITION...HAVE MAINTAINED SOME LOW PRECIPITATION CHANCES.
FOR TUESDAY AND BEYOND...ALL FOCUS IS ON THE SOUTHWESTERN U.S.
TROUGH AND HOW AND WHEN IT EJECTS OUT. MODELS REMAIN AT ODDS...WITH
THE 06.00Z GFS/CANADIAN MORE AGGRESSIVE...BRINGING A SURFACE LOW
THROUGH THE FORECAST AREA WEDNESDAY MORNING. MEANWHILE THE 06.00Z
ECMWF CONTINUES THE IDEA OF KEEPING ANY SURFACE LOW WELL TO THE
SOUTH...CROSSING THE OHIO VALLEY AND MUCH SLOWER WITH THE EJECTION
OF THE UPPER TROUGH. EITHER SCENARIO LOOKS FAVORABLE FOR
PRECIPITATION MOVING IN FOR TUESDAY NIGHT...INDUCED BY A SURGE OF
MOISTURE TRANSPORT TOWARDS THE AREA...ALONG WITH UPPER DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF A JET OVER THE GREAT LAKES. AS A
RESULT...HAVE RAISED PRECIPITATION CHANCES MORE TO THE 60-70 RANGE.
FOLLOWED A MODEL CONSENSUS FOR WEDNESDAY THROUGH FRIDAY WHICH
REQUIRES AT LEAST SOME MENTION OF PRECIPITATION ALMOST EACH DAY
EXCEPT FRIDAY. THIS IS ALL DUE TO THE UPPER TROUGH AFFECTING THE
AREA. ADDITIONALLY...COOLER AIR MOVES IN WITH THE UPPER
TROUGH...ENOUGH THAT WE COULD DEAL WITH SOME SNOW COME WEDNESDAY
NIGHT AND THURSDAY. FOLLOWED A CONSENSUS APPROACH TOO FOR
TEMPERATURES...BUT THESE MAY NEED TO BE ADJUSTED EITHER WARMER OR
COOLER ONCE MORE CERTAINTY EXISTS ON THE PRECIPITATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED 1100 PM CDT FRI APR 5 2013
PROBLEMATIC FORECAST. FIRST...SLUG OF MOISTURE/SHORTWAVE HEADED
NORTHEAST OUT OF THE SOUTHERN PLAINS...TAKING AIM ON THE REGION. SFC
OBS INDICATE A WEST-EAST RUNNING FRONT JUST NORTH OF THE TAF SITES.
LOW LEVEL WINDS ARE PICKING UP PER VAD/PROFILERS. THIS ALL SUGGESTS
THAT MORE PCPN COULD DEVELOP OVERNIGHT ACROSS THE AREA...LIKELY IN
THE VICINITY AND/OR NORTH OF THE SFC BOUNDARY. THE HRRR IS LATCHING
ONTO THIS...AND DEVELOPING A LINE ALONG THE I-90
CORRIDOR...IMPACTING KRST/KLSE. THE LATEST NAM12/RAP13 DO NOT.
PREVIOUSLY DRY LOW LAYERS HAVE EXPERIENCED SOME MOISTENING THANKS TO
THE RAIN/SNOW FROM EARLY IN THE EVENING.
MEANWHILE...THE HRRR ALSO DEVELOPS A LARGE SWATH OF PCPN WITHIN THE
MOISTURE TRANSPORT...WITH ADDITIONAL FORCING FROM THAT SHORTWAVE.
AGAIN...THE NAM12/RAP13 FAVOR DRY. THIS COULD MOVE OVER KLSE...BUT
WOULD LIKELY BE EAST OF KRST.
CONFIDENCE SHAKY IN THIS SCENARIO...ALTHOUGH THE FORCING MECHANISMS
APPEAR TO THE BE THERE AND FAVOR PCPN DEVELOPMENT. LATEST 88-D
IMAGERY POINTING TO SOME ENHANCED RETURNS IN A WEST-EAST LINE ACROSS
SOUTHERN MN. WILL MONITOR TRENDS LEADING UP TO 06Z TAFS. WILL LIKELY
KEEP DRY AND AMEND IF THE PCPN DOES MANIFEST.
IF NONE OF THAT PCPN DEVELOPS...LOWER CIGS AND INCREASING PCPN
CHANCES WILL RETURN BY LATE SAT MORNING...AHEAD OF A COLD FRONT.
TIMING OF THE FRONTAL PASSAGE AT KRST LOOKS TO BE AROUND 21Z
SAT...AND BY 00Z FOR KLSE. ENOUGH INSTABILITY THAT THERE COULD BE A
RUMBLE OR TWO OF THUNDER AHEAD OF THE FRONT - BUT NOT ENOUGH OF A
CHANCE TO ADD TO THE TAFS AT THIS TIME. GFS/NAM BUFKIT SOUNDINGS
WOULD KEEP THE LOW LAYERS SATURATED POST THE FRONT...THUS MVFR CIGS
THROUGH THE NIGHT. CONFIDENCE NOT OVERLY HIGH HERE...BUT ENOUGH OF A
SIGNAL TO LEAN THE FORECAST THAT WAY.
2 KFT WINDS ARE EXPECTED TO INCREASE TO 45-50 KTS VIA RAP BUFKIT
SOUNDINGS OVERNIGHT. MATCHES WELL WITH VAD/PROFILER DATA. HAVE ADDED
LLWS TO KLSE FROM 08-14Z TO REFLECT THIS.
&&
.HYDROLOGY...
ISSUED AT 339 AM CDT SAT APR 6 2013
RIVER STATUS...
AN ICE JAM PERSISTS ON THE BLACK RIVER ON THE NORTH SIDE OF
NEILLSVILLE. THIS ICE JAM COMBINED WITH SNOW MELT MOVING THROUGH THE
RIVER HAS RESULTED IN DIFFICULT FORECASTING DOWNSTREAM...BUT MOST OF
THE RIVER IS STILL RUNNING WITHIN BANK. THE TREMPEALEAU RIVER NEAR
DODGE REMAINS ABOVE MINOR FLOOD STAGE. ELSEWHERE...RIVERS APPEARS TO
BE STEADILY FALLING.
SNOW PACK...
THIS IS TOUGH TO SAY AS LATEST NOHRSC DATA SEEMS OVERDONE WITH THE
AMOUNT OF SNOW ON THE GROUND...COMPARED TO AT LEAST 7 AM COOP DATA
YESTERDAY. THERE MAY NOT BE MUCH SNOW LEFT ACROSS SOUTHEAST
MINNESOTA AND EVEN THE SOUTHERN PORTIONS OF BUFFALO AND TREMPEALEAU
COUNTIES. ACROSS NORTHERN PORTIONS OF THESE COUNTIES INTO TAYLOR AND
CLARK...THINKING AT LEAST 1 TO LOCALLY 4 INCHES OF WATER AMOUNT
EXISTS.
RAINFALL...
THE SYSTEM COMING THROUGH TODAY AND THIS EVENING CONTINUES TO LOOK
LESS IMPRESSIVE IN TERMS OF AMOUNTS...NOW MAYBE UP TO A 1/4 INCH.
THERE CERTAINLY COULD BE A FEW HIGHER AMOUNTS IF SOME THUNDERSTORMS
GET GOING. ANOTHER SHOT FOR RAINFALL COMES SUNDAY NIGHT INTO MONDAY
MORNING WHICH COULD TOTAL 1/4 TO 1/2 INCH. MORE RAIN IS POSSIBLE
TUESDAY THROUGH THURSDAY WITH POTENTIAL FOR MODERATE RAINFALL.
TEMPERATURES...
THERE IS BIG CONCERN TODAY FOR RAPID SNOW MELT WITH READINGS
CLIMBING INTO THE MID 40S TO MID 50S OVER THE SNOW PACK AREAS. IN
FACT...THERE IS A CHANCE SOME LOCATIONS ALONG I-94 COULD TOP OUT AT
60. MOST OF THE NEXT 7 DAYS LOOK TO HAVE DAYTIME TEMPERATURES AT
LEAST 40 FOR CONTINUED FAVORABLE SNOW MELT CONDITIONS.
FROST DEPTH...
NO RECENT REPORTS ARE AVAILABLE. AS OF APRIL 4TH...FROST DEPTHS
ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1 1/2 FEET
SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH CENTRAL
WISCONSIN. THIS FROST WILL CAUSE MUCH OF THE RUNOFF FROM SNOW MELT
RUNOFF AND PRECIPITATION TO GO INTO STREAMS AND RIVERS.
SUMMARY...
MAIN CONCERN FOR FLOODING TODAY COMES FROM SNOW PACK MELTING...DUE
TO THE WARM AIR MOVING IN...WHICH A BREEZY SOUTH WIND AND DEWPOINTS
NEAR 40 WILL AID EVEN MORE IN THE MELTING PROCESS. THE ONLY ITEMS
PRECLUDING A FLOOD WATCH RIGHT NOW IS UNCERTAINTY ON THE AMOUNT OF
SNOW AND WATER EQUIVALENT...ALONG WITH THE FACT THAT THE TREMPEALEAU
RIVER AT DODGE ALREADY HAS A FLOOD WARNING. AS WE HEAD THROUGH THE
NEXT COUPLE OF DAYS...THE AMOUNT OF SNOW AND WATER EQUIVALENT
AVAILABLE WILL BECOME EVEN MORE PROBLEMATIC. ALREADY IT APPEARS THE
FLOODING POTENTIAL FROM SNOW PACK MELTING HAS MOSTLY ENDED FOR MUCH
OF SOUTHEAST MINNESOTA...SEEING THAT THE WHITEWATER RIVER DID NOT
RISE NEARLY AS MUCH YESTERDAY. OVERALL...THE BIGGEST FLOODING
CONCERNS ARE THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS NEW YORK NY
203 AM EDT MON APR 8 2013
.SYNOPSIS...
A COLD FRONT PUSHES INTO THE REGION OVERNIGHT...THEN LIFTS TO THE
NORTH ON MONDAY. THIS FRONT THEN REMAINS NEAR THE AREA INTO
FRIDAY WITH WAVES OF LOW PRESSURE RIDING ALONG THE BOUNDARY. A
DEEPER LOW MOVES THROUGH THE REGION FRIDAY NIGHT INTO SATURDAY
CARRYING THE A COLD EAST OF THE REGION SATURDAY MORNING. HIGH
PRESSURE BUILDS IN FOR SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
BASED ON LATEST SATELLITE TRENDS SHOWING CLOUD COVER FROM PA BACK
INTO OHIO VALLEY HEADED EAST IN ZONAL FLOW ALOFT - HAVE INCREASED
CLOUD COVER OVERNIGHT. LATEST RADAR RETURNS AND RUC ANALYSIS
SHOWING NO UPSTREAM VORTICITY MAXIMUM TO MOVE THROUGH OVERNIGHT -
SUPPORT A DRY FORECAST.
MINOR CHANGES MADE TO TEMPERATURES/DEWPOINTS REFLECTING BLEND OF
LAV/MET/MAV GUIDANCE. STILL ON TRACK FOR LOWS AROUND 5 DEGREES
ABOVE NORMAL - MAYBE A TAD HIGHER IN NYC.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
A DRY MONDAY IS EXPECTED AS A BRIEF PERIOD OF WEAK RIDGING WILL
MOVE OVER THE REGION. DAYTIME HIGH TEMPERATURES ARE EXPECTED TO
CLIMB INTO THE UPPER 60S AND LOWER 70S ACROSS THE INTERIOR.
ACROSS THE COASTAL LOCATIONS...HIGHS WILL REACH THE LOWER AND
MIDDLE 60S...COURTESY OF AN ONSHORE FLOW. THIS WILL BE ABOUT 10
DEGREES ABOVE NORMAL. FOLLOWED A MAV/MET BLEND.
CLOUDY SKIES AND A CHANCE OF SHOWERS RETURNS TO THE FORECAST
MONDAY NIGHT...IN RESPONSE TO ANOTHER PASSING MID-LEVEL SHORTWAVE
AND THE PASSAGE OF AN 850 WARM FRONT. WILL KEEP POPS AT CHANCE
FOR NOW. FOLLOWED A MAV/MET BLEND FOR OVERNIGHT LOWS. TEMPERATURES
ARE EXPECTED TO ONLY FALL INTO THE UPPER 40S AND LOWER 50S...ABOUT
10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MUCH OF THE LONG RANGE FORECAST REMAINS UNCERTAIN AND WILL BE
HIGHLY DEPENDENT ON THE SETUP OF A FRONTAL BOUNDARY. CURRENT
THINKING AND RECENT MODEL RUNS KEEP THE BOUNDARY JUST NORTH OF THE
AREA. THIS WILL RESULT IN A WARM AIRMASS ACROSS THE REGION...WITH
COASTAL AREAS REMAINING COOLER IN THE SOUTHERLY FLOW. CLOUDS WILL
BE IN THE VICINITY TUESDAY AND WITH THE FRONTAL BOUNDARY IN THE
AREA...LOWERED THE HIGHS FOR TUESDAY. HOWEVER MODEL SPREAD
INDICATES HIGHS INLAND FROM 70 TO 79...AND ALONG THE COAST FROM 62
TO 75...WITH THE UNCERTAINTY FORECAST HIGHS SOMEWHERE ABOUT IN THE
MIDDLE OF THE SPREAD. WIDE SPREADS IN FORECAST HIGHS AND LOWS
REMAIN WEDNESDAY INTO FRIDAY. WITH WAVES OF LOW PRESSURE EXPECTED
TO TRACK ALONG THE FRONTAL BOUNDARY AND EMBEDDED SHORTWAVES ALSO
TRAVEL THROUGH THE UPPER ZONAL FLOW THERE WILL BE A CHANCE OF
SHOWERS TUESDAY NIGHT INTO SATURDAY. ELEVATED INSTABILITY WILL BE
VERY MARGINAL AND AVAILABLE MIXED LAYER CAPE WILL BE NEAR ZERO
WITH HIGHER CINS...SO REMOVED MENTION OF THUNDER.
BEST CHANCE OF SHOWERS WILL BE A DEEPER SHORTWAVE AND VORTICITY
MAXIMUM MOVING OUT OF THE NORTHERN PLAINS AND INTO THE NORTHEAST
FRIDAY AND FRIDAY NIGHT...AND THUS WILL HAVE THE HIGHEST POPS OF
THE EXTENDED DURING THIS TIME FROM. RATHER STRONG COLD FRONT WILL
BE PASSING THROUGH WITH THIS WAVE WITH TEMPERATURES RETURNING TO
BELOW NORMAL SEASONAL LEVELS FOR NEXT WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
VFR TODAY WITH LIGHT BUT SHIFTING WINDS AS A WEAK COLD FRONT
STALLS OVER THE AREA.
LOCALIZED LIGHT FOG IS POSSIBLE OUTSIDE OF THE NY METRO PRIOR TO
SUNRISE OTHERWISE NO RESTRICTIONS. LIGHT WINDS VEER THIS MORNING
WITH A LIGHT NORTHERLY FLOW BEFORE SEA BREEZE CIRCULATION DEVELOP
THIS AFTERNOON ALONG COASTAL AREAS. TIMING OF WIND DIRECTIONS
CHANGES COULD BE OF BY + OR - 2 HOURS.
.OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MON NIGHT...MVFR IN BR POSSIBLE WITH LOW CHC OF IFR CIGS.
.TUE-THU...GENERALLY VFR. SUB-VFR MAY OCCUR AT TIMES IN
SCATTERED RAIN SHOWERS WITH ISOLATED TSTMS. LGT WNDS.
.FRI...OCNL MVFR IN SCATTERED SHRA AND TSTMS.
&&
.MARINE...
WINDS HAVE FALLEN BELOW SCA LEVELS ON THE COASTAL OCEAN ZONES AND
WILL CONTINUE TO FALL OVERNIGHT. SEAS REMAIN RIGHT BELOW 5 FT -
AND WITH DIMINISHING WINDS DO NOT EXPECT THEM TO INCREASE ANY - IN
FACT WOULD EXPECT A SLIGHT FALL OFF. AS A RESULT HAVE CANCELLED
THE SMALL CRAFT ADVISORY FOR THE COASTAL OCEAN WATERS.
ALL WATERS WILL BE BELOW SMALL CRAFT LEVELS ON MONDAY BEFORE SEAS
INCREASE ONCE AGAIN MONDAY NIGHT.
SEAS ON THE OCEAN WATERS WILL LIKELY STILL BE AT OR ABOVE 5 FT
TUESDAY MORNING AS A STRONG SOUTHERLY FLOW CONTINUES. AS THE FLOW
DIMINISHES THROUGH THE DAY AND INTO TUESDAY NIGHT SEAS WILL ALSO
SUBSIDE AND DROP BELOW SMALL CRAFT DURING THE EVENING. THE
FORECAST OF WINDS AND SEAS WILL BE DEPENDENT ON WHERE A FRONTAL
BOUNDARY BECOMES STATIONARY IN THE VICINITY. CURRENT THINKING IS
THAT THE FRONT WILL BE JUST NORTH OF THE WATERS THROUGH THURSDAY
NIGHT. A SOUTHERLY FLOW WILL PERSIST AND WINDS WILL REMAIN BELOW
SMALL CRAFT. HOWEVER...BY WEDNESDAY NIGHT SEAS ON THE OCEAN WATERS
ARE EXPECTED TO BUILD BACK TO SMALL CRAFT WITH A STRENGTHENING AND
PERSISTENT SOUTH FLOW. AND THEN SUBSIDE AGAIN AS A DEEPER WAVE OF
LOW PRESSURE RIDES ALONG THE STALLED FRONTAL BOUNDARY...AND THE
GRADIENT BECOMES RATHER WEAK. THEN A NORTHWEST FLOW SETS UP BEHIND
THE DEPARTING LOW FRIDAY NIGHT INTO SATURDAY. GUSTS AT THAT TIME
FRAME MAY BE NEAR SMALL CRAFT.
&&
.HYDROLOGY...
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED THROUGH
THURSDAY. THERE IS A HIGH DEGREE OF UNCERTAINTY WITH THE FORECAST
THROUGH THE WEEK AND ANY PRECIPITATION AND AMOUNTS WILL BE
DEPENDENT ON WHERE A FRONTAL BOUNDARY SETS UP AND THE TIMING OF
WAVES OF LOW PRESSURE MOVING ALONG THE BOUNDARY. THE BEST CHANCE
FOR SIGNIFICANT RAINFALL APPEARS TO BE LATE IN THE WEEK...THURSDAY
NIGHT INTO FRIDAY NIGHT...WITH INCREASING PRECIPITABLE WATER
VALUES ACROSS THE REGION...AND FAIRLY STRONG FORCING AVAILABLE TO
ACT ON THIS MOISTURE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BC/MET
NEAR TERM...MALOIT
SHORT TERM...BC
LONG TERM...MET
AVIATION...TONGUE
MARINE...BC/MALOIT/MET/PW
HYDROLOGY...BC/MET
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1239 AM EDT MON APR 8 2013
.SYNOPSIS...
A COLD FRONT PUSHES INTO THE REGION OVERNIGHT...THEN LIFTS TO THE
NORTH ON MONDAY. THIS FRONT THEN REMAINS NEAR THE AREA INTO
FRIDAY WITH WAVES OF LOW PRESSURE RIDING ALONG THE BOUNDARY. A
DEEPER LOW MOVES THROUGH THE REGION FRIDAY NIGHT INTO SATURDAY
CARRYING THE A COLD EAST OF THE REGION SATURDAY MORNING. HIGH
PRESSURE BUILDS IN FOR SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
BASED ON LATEST SATELLITE TRENDS SHOWING CLOUD COVER FROM PA BACK
INTO OHIO VALLEY HEADED EAST IN ZONAL FLOW ALOFT - HAVE INCREASED
CLOUD COVER OVERNIGHT. LATEST RADAR RETURNS AND RUC ANALYSIS
SHOWING NO UPSTREAM VORTICITY MAXIMUM TO MOVE THROUGH OVERNIGHT -
SUPPORT A DRY FORECAST.
MINOR CHANGES MADE TO TEMPERATURES/DEWPOINTS REFLECTING BLEND OF
LAV/MET/MAV GUIDANCE. STILL ON TRACK FOR LOWS AROUND 5 DEGREES
ABOVE NORMAL - MAYBE A TAD HIGHER IN NYC.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
A DRY MONDAY IS EXPECTED AS A BRIEF PERIOD OF WEAK RIDGING WILL
MOVE OVER THE REGION. DAYTIME HIGH TEMPERATURES ARE EXPECTED TO
CLIMB INTO THE UPPER 60S AND LOWER 70S ACROSS THE INTERIOR.
ACROSS THE COASTAL LOCATIONS...HIGHS WILL REACH THE LOWER AND
MIDDLE 60S...COURTESY OF AN ONSHORE FLOW. THIS WILL BE ABOUT 10
DEGREES ABOVE NORMAL. FOLLOWED A MAV/MET BLEND.
CLOUDY SKIES AND A CHANCE OF SHOWERS RETURNS TO THE FORECAST
MONDAY NIGHT...IN RESPONSE TO ANOTHER PASSING MID-LEVEL SHORTWAVE
AND THE PASSAGE OF AN 850 WARM FRONT. WILL KEEP POPS AT CHANCE
FOR NOW. FOLLOWED A MAV/MET BLEND FOR OVERNIGHT LOWS. TEMPERATURES
ARE EXPECTED TO ONLY FALL INTO THE UPPER 40S AND LOWER 50S...ABOUT
10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MUCH OF THE LONG RANGE FORECAST REMAINS UNCERTAIN AND WILL BE
HIGHLY DEPENDENT ON THE SETUP OF A FRONTAL BOUNDARY. CURRENT
THINKING AND RECENT MODEL RUNS KEEP THE BOUNDARY JUST NORTH OF THE
AREA. THIS WILL RESULT IN A WARM AIRMASS ACROSS THE REGION...WITH
COASTAL AREAS REMAINING COOLER IN THE SOUTHERLY FLOW. CLOUDS WILL
BE IN THE VICINITY TUESDAY AND WITH THE FRONTAL BOUNDARY IN THE
AREA...LOWERED THE HIGHS FOR TUESDAY. HOWEVER MODEL SPREAD
INDICATES HIGHS INLAND FROM 70 TO 79...AND ALONG THE COAST FROM 62
TO 75...WITH THE UNCERTAINTY FORECAST HIGHS SOMEWHERE ABOUT IN THE
MIDDLE OF THE SPREAD. WIDE SPREADS IN FORECAST HIGHS AND LOWS
REMAIN WEDNESDAY INTO FRIDAY. WITH WAVES OF LOW PRESSURE EXPECTED
TO TRACK ALONG THE FRONTAL BOUNDARY AND EMBEDDED SHORTWAVES ALSO
TRAVEL THROUGH THE UPPER ZONAL FLOW THERE WILL BE A CHANCE OF
SHOWERS TUESDAY NIGHT INTO SATURDAY. ELEVATED INSTABILITY WILL BE
VERY MARGINAL AND AVAILABLE MIXED LAYER CAPE WILL BE NEAR ZERO
WITH HIGHER CINS...SO REMOVED MENTION OF THUNDER.
BEST CHANCE OF SHOWERS WILL BE A DEEPER SHORTWAVE AND VORTICITY
MAXIMUM MOVING OUT OF THE NORTHERN PLAINS AND INTO THE NORTHEAST
FRIDAY AND FRIDAY NIGHT...AND THUS WILL HAVE THE HIGHEST POPS OF
THE EXTENDED DURING THIS TIME FROM. RATHER STRONG COLD FRONT WILL
BE PASSING THROUGH WITH THIS WAVE WITH TEMPERATURES RETURNING TO
BELOW NORMAL SEASONAL LEVELS FOR NEXT WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A COLD FRONT APPROACHES FROM THE WEST AND STALLS OVER THE AREA
OVERNIGHT THROUGH MONDAY.
GENERALLY VFR. AFTER MIDNIGHT...PATCHY FOG MAY DEVELOP OUTSIDE OF
NYC METRO TERMINALS. CONFIDENCE IS LOW THOUGH. OVERALL...LOCAL
MVFR VSBYS CAN NOT BE RULED OUT. OTHERWISE MID AND HIGH CLOUDS
DEPART.
WINDS ARE LIGHTENING AS EXPECTED FROM THE SOUTH THIS
EVENING...THEN TURN TOWARD THE WEST/SOUTHWEST AFTER MIDNIGHT.
ALTHOUGH LOW LEVEL WIND SHEAR IS ONLY INDICATED AT KISP...NOTE
THAT 40-50 KT WINDS ARE POSSIBLE AT 2000FT AT MOST OF THE OTHER
TERMINALS THROUGH MIDNIGHT OR SO.
WINDS TURN TOWARD THE NORTHWEST AFTER SUNRISE MONDAY...BUT REMAIN
UNDER 10 KTS. THEN WINDS TURN BACK TO THE SOUTH DURING THE
AFTERNOON. PLEASE SEE INDIVIDUAL TERMINAL FORECASTS FOR BEST
ESTIMATE ON TIMING OF WIND SHIFTS. ALL WIND SHIFTS COULD BE OFF BY
AN HOUR OR TWO.
.OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MONDAY NIGHT...SUB-VFR IS POSSIBLE IN PATCHY FOG AND STRATUS.
SHOWERS ARE ALSO POSSIBLE.
.TUESDAY-FRIDAY...GENERALLY VFR BUT SUB-VFR MAY OCCUR AT TIMES IN
RAIN SHOWERS WITH ISOLATED TSTMS.
&&
.MARINE...
WINDS HAVE FALLEN BELOW SCA LEVELS ON THE COASTAL OCEAN ZONES AND
WILL CONTINUE TO FALL OVERNIGHT. SEAS REMAIN RIGHT BELOW 5 FT -
AND WITH DIMINISHING WINDS DO NOT EXPECT THEM TO INCREASE ANY - IN
FACT WOULD EXPECT A SLIGHT FALL OFF. AS A RESULT HAVE CANCELLED
THE SMALL CRAFT ADVISORY FOR THE COASTAL OCEAN WATERS.
ALL WATERS WILL BE BELOW SMALL CRAFT LEVELS ON MONDAY BEFORE SEAS
INCREASE ONCE AGAIN MONDAY NIGHT.
SEAS ON THE OCEAN WATERS WILL LIKELY STILL BE AT OR ABOVE 5 FT
TUESDAY MORNING AS A STRONG SOUTHERLY FLOW CONTINUES. AS THE FLOW
DIMINISHES THROUGH THE DAY AND INTO TUESDAY NIGHT SEAS WILL ALSO
SUBSIDE AND DROP BELOW SMALL CRAFT DURING THE EVENING. THE
FORECAST OF WINDS AND SEAS WILL BE DEPENDENT ON WHERE A FRONTAL
BOUNDARY BECOMES STATIONARY IN THE VICINITY. CURRENT THINKING IS
THAT THE FRONT WILL BE JUST NORTH OF THE WATERS THROUGH THURSDAY
NIGHT. A SOUTHERLY FLOW WILL PERSIST AND WINDS WILL REMAIN BELOW
SMALL CRAFT. HOWEVER...BY WEDNESDAY NIGHT SEAS ON THE OCEAN WATERS
ARE EXPECTED TO BUILD BACK TO SMALL CRAFT WITH A STRENGTHENING AND
PERSISTENT SOUTH FLOW. AND THEN SUBSIDE AGAIN AS A DEEPER WAVE OF
LOW PRESSURE RIDES ALONG THE STALLED FRONTAL BOUNDARY...AND THE
GRADIENT BECOMES RATHER WEAK. THEN A NORTHWEST FLOW SETS UP BEHIND
THE DEPARTING LOW FRIDAY NIGHT INTO SATURDAY. GUSTS AT THAT TIME
FRAME MAY BE NEAR SMALL CRAFT.
&&
.HYDROLOGY...
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED THROUGH
THURSDAY. THERE IS A HIGH DEGREE OF UNCERTAINTY WITH THE FORECAST
THROUGH THE WEEK AND ANY PRECIPITATION AND AMOUNTS WILL BE
DEPENDENT ON WHERE A FRONTAL BOUNDARY SETS UP AND THE TIMING OF
WAVES OF LOW PRESSURE MOVING ALONG THE BOUNDARY. THE BEST CHANCE
FOR SIGNIFICANT RAINFALL APPEARS TO BE LATE IN THE WEEK...THURSDAY
NIGHT INTO FRIDAY NIGHT...WITH INCREASING PRECIPITABLE WATER
VALUES ACROSS THE REGION...AND FAIRLY STRONG FORCING AVAILABLE TO
ACT ON THIS MOISTURE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/BC/MET
NEAR TERM...MALOIT
SHORT TERM...BC
LONG TERM...MET
AVIATION...PW
MARINE...MALOIT/BC/MET
HYDROLOGY...BC/MET
AREA FORECAST DISCUSSION
NWS MIAMI FL
144 AM EDT MON APR 8 2013
.AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE PERIOD.
GENERALLY LIGHT EASTERLY FLOW IS EXPECTED AT ALL SITES THROUGH THE
MORNING BEFORE INCREASING BY AFTERNOON. KAPF SHOULD SEE A GULF
BREEZE DEVELOP BY MID AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 812 PM EDT SUN APR 7 2013/
UPDATE...
A MID TO UPPER LEVEL TROUGH MOVED THROUGH THE FLORIDA PENINSULA
THIS AFTERNOON ALLOWING FOR A FEW SHOWERS TO DEVELOP OVER THE
AREA. THE TROUGH WILL CONTINUE TO MOVE EAST AWAY FROM SOUTH
FLORIDA TONIGHT...AS THE SURFACE HIGH REMAINS OVER THE WESTERN
ATLANTIC WATERS. THIS WILL ALLOW FOR DRY AIR TO WORK BACK INTO THE
AREA FOR TONIGHT. SO WILL KEEP THE WEATHER DRY OVER SOUTH FLORIDA
TONIGHT ALONG WITH MOSTLY CLEAR TO CLEAR SKIES. TEMPERATURES
TONIGHT SHOULD BE ABLE TO FALL INTO THE 60S TONIGHT OVER SOUTH
FLORIDA...DUE TO THE CLEAR SKIES AND LIGHT WINDS OVERNIGHT.
SO THE ONLY CHANGE TO THE FORECAST FOR TONIGHT IS TO REMOVE THE
AFTERNOON AND EVENING WORDING FROM THE ZONES.
UPDATE...54/BNB
PREV DISCUSSION... /ISSUED 219 PM EDT SUN APR 7 2013/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
PLACED AN ISOLATED POP GRID FOR ALL ZONES THE REMAINDER OF THIS
AFTERNOON. THE ONSHORE FLOW OF A FEW SHOWERS ALONG THE EAST COAST
HAS BEEN PERSISTENT AND THE HRRR DOES INDICATE A CONTINUATION OF
ISOLATED ACTIVITY DEVELOPING ACROSS THE INTERIOR AND COASTAL
COLLIER COUNTY UNTIL VERY EARLY THIS EVENING.
GLOBAL MODELS IN VERY GOOD AGREEMENT OVER THE NEXT 48-60 HOURS
WITH MID LEVEL ZONAL FLOW THROUGH EARLY TUESDAY AND SURFACE HIGH
PRESSURE ACROSS THE ATLANTIC AND NORTH FLORIDA. THIS WILL MAINTAIN
A MODEST EASTERLY LOW LEVEL WIND FLOW AND A MOSTLY DRY WEATHER
REGIME WITH STRONG SUBSIDENCE CAP REMAINING INTACT. THERE IS A
SMALL INCREASE IN PWAT VALUES THAT WILL BE ROTATING WESTWARD
BENEATH THE LARGE SCALE LOW LEVEL RIDGE OVER THE ATLANTIC THAT THE
MODELS SHOW ARRIVING ACROSS SOUTH FLORIDA BY LATE TUESDAY AND
TUESDAY NIGHT. FORECAST SOUNDINGS ALSO INDICATE THE CAP WILL BEGIN
TO ERODE BY THIS TIME AND THIS SHOULD ALLOW FOR A SLIGHT INCREASE
IN SHOWER ACTIVITY MOVING FROM THE ATLANTIC ONTO THE SOUTHEAST
COAST. FOR THIS REASON, WILL MAINTAIN A SLIGHT CHANCE POP ALONG
THE EAST COAST TUESDAY NIGHT AND SILENT POP ELSEWHERE AS RAIN
CHANCES OVER THE INTERIOR AND COASTAL COLLIER COUNTY WILL BE TOO
SMALL TO MENTION IN THOSE LOCATIONS. IN ADDITION, THE SHORT RANGE
ENSEMBLE (SREF) IS SHOWING A SUBSTANTIAL INCREASED CHANCE FOR FOG
OVER THE INTERIOR AND SOUTHWEST COAST FOR MONDAY NIGHT AND TUESDAY
NIGHT AS THE LOW LEVEL MOISTURE INCREASES SO WILL INTRODUCE PATCHY
FOG FOR THOSE LOCATIONS AT THAT TIME.
LONG TERM (WEDNESDAY THROUGH SUNDAY)...
LOOKING AHEAD TOWARDS THE MIDDLE AND END OF THE WEEK, THE FORECAST
BECOMES INCREASINGLY UNCERTAIN AS THE GFS AND ECMWF CONTINUE TO
DIVERGE ON THE EVOLUTION OF THE POWERFUL MID LEVEL TROUGH THAT WILL
BE MOVING INTO THE CENTRAL PLAINS STATES MONDAY NIGHT AND TUESDAY
THEN SHIFTING EAST THROUGH THE WEEK. THE GFS PHASES IT IN WITH A
NORTHERN STREAM TROUGH BY LATE WEDNESDAY AND THURSDAY AS THE MAIN
SYSTEM LIFTS EAST INTO THE ATLANTIC. THIS BRINGS A TRAILING COLD
FRONT ACROSS SOUTH FLORIDA ON FRIDAY SLOWLY PUSHING THROUGH THE
REGION AND OFF THE SOUTHEAST COAST LATE SATURDAY AND SUNDAY. THIS
WOULD ALSO BRING AN INCREASED CHANCE FOR CONVECTION ON FRIDAY AND
POSSIBLY LINGERING INTO SATURDAY AS SHOWN BY THE LATEST MEX
GUIDANCE. HOWEVER, THE ECMWF IS ALSO HOLDING ONTO ITS SLOWER
SOLUTION WITH THE CENTRAL PLAINS TROUGH PHASING WITH THE UPSTREAM
SYSTEM BUT FARTHER TO THE NORTH. IT THEN SHOWS THE FRONT STALLING
ACROSS CENTRAL FLORIDA SATURDAY AND SUNDAY SO THE HIGHEST POPS WOULD
BE OVER NEXT WEEKEND. AT THIS TIME, IT IS A WAIT AND SEE APPROACH
WITH LITTLE CHANGE TO THE CURRENT FORECAST.
MARINE...
WIND AND SEAS WILL REMAIN BELOW ADVISORY LEVELS THROUGH THE END OF
THIS WEEK WITH A LIGHT TO MODERATE EAST TO SOUTHEAST WIND AND SEAS
OF 5 FEET OR LESS. THE WIND WILL INCREASE AND BECOME MORE
SOUTHERLY BY FRIDAY AS A COLD FRONT MOVES INTO NORTH FLORIDA AND
THE HIGH PRESSURE SHIFTS FARTHER EAST INTO THE ATLANTIC.
FIRE WEATHER...
RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL THRESHOLDS
THROUGH THE END OF THIS WEEK AS LOW LEVEL MOISTURE WILL CONTINUE
TO INCREASE. THIS WILL ALSO INCREASE THE LIKELIHOOD FOR SOME LATE
NIGHT FOG FORMATION OVER THE INTERIOR AND SOUTHWEST COAST AS THE
WEEK PROGRESSES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 69 81 72 83 / 10 10 20 20
FORT LAUDERDALE 70 82 73 83 / 10 10 20 20
MIAMI 71 82 71 83 / 10 10 20 20
NAPLES 65 84 69 89 / - 10 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION...CORRECTED
NWS GOODLAND KS
359 AM MDT MON APR 8 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 357 AM MDT MON APR 8 2013
UNSETTLED/ACTIVE PATTERN EXPECTED THROUGH WED AS STRONG UPPER LOW
DEVELOPS OVER FOUR CORNERS REGION TODAY AND MOVES ACROSS PLAINS
THROUGH MIDWEEK.
DENSE FOG HAS DEVELOPED EARLY THIS MORNING ACROSS EASTERN PARTS OF
THE CWA. WITH TD VALUES ONLY EXPECTED TO INCREASE IN THE EAST IT IS
REASONABLE TO ASSUME THESE CONDITIONS WILL CONTINUE. RUC/NAM SUPPORT
THIS...SHOWING LOW VISIBILITIES THROUGH 14-15Z TIME-FRAME ACROSS
EASTERN LOCATIONS. I WENT AHEAD AND ISSUED AN DENSE FOG ADVISORY FOR
THE EASTERN TIER OF THE CWA THROUGH 15Z...AND MAY HAVE TO EXPAND
FURTHER BASED ON TRENDS.
THIS AFTERNOON/EVENING...PRIMARY CONCERN CONTINUES TO BE POTENTIAL
FOR SEVERE THUNDERSTORMS ACROSS THE CWA WITH GOOD INSTABILITY AND
VERY STRONG SHEER THIS AFTERNOON/EVENING. MAIN QUESTION IS
WHERE INITIATION WILL OCCUR DURING DAY TODAY AND COVERAGE. LARGE
SCALE FORCING SHOULD STILL BE WELL TO THE WEST TODAY WITH H3 JET
STREAK NOT IN FAVORABLE LOCATION UNTIL LATER TONIGHT. WITH THIS IN
MIND...SURFACE CONVERGENCE ALONG FRONT/DRY LINE AND SURFACE TROUGH
SHOULD ACT AS MAIN FOCUS FOR INITIATION THIS AFTERNOON/EVENING. I
ADJUSTED TIMING COVERAGE THIS AFTERNOON WITH BETTER CHANCES AFTER
00Z. WITH LOW STRATUS POSSIBLY OVERSPREADING CWA AND LINGERING
THIS MORNING...WE COULD SEE A DELAY IN INITIATION AND MUCH LESS
SURFACE BASED CAPE IN THE EAST. SOUNDING ANALYSIS WOULD STILL
SUPPORT ELEVATED INSTABILITY IF THIS WERE TO OCCUR...SO I KEPT
MENTION IN PLACE FOR NOW...THOUGH THIS IS STILL A CONCERN. WITH
THE ADVERTISED SHEER PROFILES...IF ANYTHING DOES INITIATE AND
MOVE INTO OUR CWA LATE THIS AFTERNOON/EVENING THERE IS AN INCREASED
LIKELIHOOD IT WILL BECOME SUPERCELLULAR WITH VERY LARGE HAIL AND
TORNADOES POSSIBLE.
TONIGHT-WEDNESDAY...INSTABILITY AXIS QUICKLY SHIFTS EAST LATE THIS
EVENING...AS VERY STRONG COLD FRONT MOVES IN FROM NORTH. STRONG
FORCING AND GOOD MOISTURE ADVECTION SHOULD OVERSPREAD THE CWA LATE
TONIGHT ACROSS WESTERN LOCATIONS. THE RESULT SHOULD BE DIMINISHED
CHANCES FOR THUNDERSTORMS BY 06Z...WHILE THE OVERALL PRECIP COVERAGE
INCREASES. AN UNSEASONABLY COLD AIRMASS WILL OVERSPREAD THE CWA
FROM THE NW TO SE THROUGH TUESDAY MORNING WITH RAIN TRANSITIONING
TO EITHER SNOW OR FREEZING RAIN/DRIZZLE. SOUNDINGS ARE VERY CLOSE
IN RESPECT TO SNOW OR FREEZING PRECIP...AND DEPENDING ON MODEL
CHOICE ONE OR THE OTHER WILL BE THE DOMINATE PRECIP TYPE DURING
THE DAY TUESDAY. THIS IS A CONCERN IF WE END UP WITH MAINLY
FREEZING RAIN/DRIZZLE AND MAY NEED TO ISSUE ADVISORY ACCORDINGLY
FOR MUCH OF CWA. THIS WOULD ALSO RESULT IN LESS SNOW THAN
CURRENTLY ADVERTISED FOR NW LOCATIONS. BY TUESDAY NIGHT ALL PRECIP
SHOULD BE SNOW...THOUGH BULK OF LIFT/MOISTURE WILL BE
TRANSITIONING NORTH AND EAST OF THE AREA...SO WE PROBABLY WONT BE
SEEING MUCH IN THE WAY OF ADDITIONAL SNOW AFTER TUESDAY EVENING.
REGARDING WINTER STORM WATCH...THERE IS TOO MUCH UNCERTAINTY TO
EXPAND OR CANCEL AT THIS POINT. THERE IS STILL POTENTIAL FOR 3-6"
SNOW TOTALS IN NW YUMA COUNTY IF THEY SEE PRIMARILY SNOW DURING THE
DAY TUESDAY AND TRACK REMAINS FAVORABLE. I AM NOT CONFIDENT ENOUGH
TO UPGRADE AT THIS POINT TO WARNING OR ADVISORY...WITH SOME GUIDANCE
SHOWING MAIN SNOW BAND FURTHER WEST AND NORTH. I THINK WE WILL
PROBABLY NEED AN ADVISORY OF SOME SORT WITH POTENTIAL FOR STRONG
WINDS/BLOWING SNOW/FREEZING DRIZZLE/LIGHT SNOW ACROSS THE
NORTHWEST HALF OF THE CWA. THERE ARE JUST TOO MANY QUESTIONS RIGHT
NOW TO ZERO IN ON HOW THIS WILL EVOLVE...AND WHAT FLAVOR OF HAZARD
WE WILL NEED.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 233 AM MDT MON APR 8 2013
SOME DISAGREEMENT AND UNCERTAINTY THROUGH THIS PERIOD...ESPECIALLY
EARLY ON. IN GENERAL...DETERMINISTIC AND ENSEMBLE OUTPUT SUPPORT
A ZONAL OR NEARLY ZONAL FLOW THROUGH THIS PERIOD WITH MANY SMALL
SCALE SHORTWAVE TROUGHS MOVING THROUGH. MODELS HAVING TROUBLE
RESOLVING WHAT IS GOING TO HAPPEN IN THE SHORT TERM AND THAT HAS
AFFECTS INTO THIS PERIOD. MODELS DISAGREE ON THE FLOW ALOFT AND
SHORTWAVES IN THIS FLOW THROUGH THIS PERIOD. THE CRH_INIT HAS
GIVEN ME SOME SLIGHT CHANCE POPS THURSDAY NIGHT AND ONCE AGAIN
FROM FRIDAY NIGHT INTO SATURDAY MORNING. GIVEN THE PROBLEMS
DISCUSSED ABOVE AND SINCE ONLY SLIGHT CHANCE WILL NOT MAKE ANY
CHANGES TO THESE GRIDS. OTHERWISE LOOKS DRY FOR THE REST OF THE
PERIOD.
LEFT REMAINING GRIDS ALONE AS WELL. LOOKS LIKE A WARMING TREND
OCCURS THROUGH THIS PERIOD AND THIS LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE
INITIATION...BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME
SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ003-004-
015-016-029.
CO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ090.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
358 AM MDT MON APR 8 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 357 AM MDT MON APR 8 2013
UNSETTLED/ACTIVE PATTERN EXPECTED THROUGH WED AS STRONG UPPER LOW
DEVELOPS OVER FOUR CORNERS REGION TODAY AND MOVES ACROSS PLAINS
THROUGH MIDWEEK.
DENSE FOG HAS DEVELOPED EARLY THIS MORNING ACROSS EASTERN PARTS OF
THE CWA. WITH TD VALUES ONLY EXPECTED TO INCREASE IN THE EAST IT IS
REASONABLE TO ASSUME THESE CONDITIONS WILL CONTINUE. RUC/NAM SUPPORT
THIS...SHOWING LOW VISIBILITIES THROUGH 14-15Z TIME-FRAME ACROSS
EASTERN LOCATIONS. I WENT AHEAD AND ISSUED AN DENSE FOG ADVISORY FOR
THE EASTERN TIER OF THE CWA THROUGH 15Z...AND MAY HAVE TO EXPAND
FURTHER BASED ON TRENDS.
THIS AFTERNOON/EVENING...PRIMARY CONCERN CONTINUES TO BE POTENTIAL
FOR SEVERE THUNDERSTORMS ACROSS THE CWA WITH GOOD INSTABILITY AND
VERY STRONG SHEER THIS AFTERNOON/EVENING. MAIN QUESTION IS
WHERE INITIATION WILL OCCUR DURING DAY TODAY AND COVERAGE. LARGE
SCALE FORCING SHOULD STILL BE WELL TO THE WEST TODAY WITH H3 JET
STREAK NOT IN FAVORABLE LOCATION UNTIL LATER TONIGHT. WITH THIS IN
MIND...SURFACE CONVERGENCE ALONG FRONT/DRY LINE AND SURFACE TROUGH
SHOULD ACT AS MAIN FOCUS FOR INITIATION THIS AFTERNOON/EVENING. I
ADJUSTED TIMING COVERAGE THIS AFTERNOON WITH BETTER CHANCES AFTER
00Z. WITH LOW STRATUS POSSIBLY OVERSPREADING CWA AND LINGERING
THIS MORNING...WE COULD SEE A DELAY IN INITIATION AND MUCH LESS
SURFACE BASED CAPE IN THE EAST. SOUNDING ANALYSIS WOULD STILL
SUPPORT ELEVATED INSTABILITY IF THIS WERE TO OCCUR...SO I KEPT
MENTION IN PLACE FOR NOW...THOUGH THIS IS STILL A CONCERN. WITH
THE ADVERTISED SHEER PROFILES...IF ANYTHING DOES INITIATE AND
MOVE INTO OUR CWA LATE THIS AFTERNOON/EVENING THERE IS AN INCREASED
LIKELIHOOD IT WILL BECOME SUPERCELLULAR WITH VERY LARGE HAIL AND
TORNADOES POSSIBLE.
TONIGHT-WEDNESDAY...INSTABILITY AXIS QUICKLY SHIFTS EAST LATE THIS
EVENING...AS VERY STRONG COLD FRONT MOVES IN FROM NORTH. STRONG
FORCING AND GOOD MOISTURE ADVECTION SHOULD OVERSPREAD THE CWA LATE
TONIGHT ACROSS WESTERN LOCATIONS. THE RESULT SHOULD BE DIMINISHED
CHANCES FOR THUNDERSTORMS BY 06Z...WHILE THE OVERALL PRECIP COVERAGE
INCREASES. AN UNSEASONABLY COLD AIRMASS WILL OVERSPREAD THE CWA
FROM THE NW TO SE THROUGH TUESDAY MORNING WITH RAIN TRANSITIONING
TO EITHER SNOW OR FREEZING RAIN/DRIZZLE. SOUNDINGS ARE VERY CLOSE
IN RESPECT TO SNOW OR FREEZING PRECIP...AND DEPENDING ON MODEL
CHOICE ONE OR THE OTHER WILL BE THE DOMINATE PRECIP TYPE DURING
THE DAY TUESDAY. THIS IS A CONCERN IF WE END UP WITH MAINLY
FREEZING RAIN/DRIZZLE AND MAY NEED TO ISSUE ADVISORY ACCORDINGLY
FOR MUCH OF CWA. THIS WOULD ALSO RESULT IN LESS SNOW THAN
CURRENTLY ADVERTISED FOR NW LOCATIONS. BY TUESDAY NIGHT ALL PRECIP
SHOULD BE SNOW...THOUGH BULK OF LIFT/MOISTURE WILL BE
TRANSITIONING NORTH AND EAST OF THE AREA...SO WE PROBABLY WONT BE
SEEING MUCH IN THE WAY OF ADDITIONAL SNOW AFTER TUESDAY EVENING.
REGARDING WINTER STORM WATCH...THERE IS TOO MUCH UNCERTAINTY TO
EXPAND OR CANCEL AT THIS POINT. THERE IS STILL POTENTIAL FOR 3-6"
SNOW TOTALS IN NW YUMA COUNTY IF THEY SEE PRIMARILY SNOW DURING THE
DAY TUESDAY AND TRACK REMAINS FAVORABLE. I AM NOT CONFIDENT ENOUGH
TO UPGRADE AT THIS POINT TO WARNING OR ADVISORY...WITH SOME GUIDANCE
SHOWING MAIN SNOW BAND FURTHER WEST AND NORTH. I THINK WE WILL
PROBABLY NEED AN ADVISORY OF SOME SORT WITH POTENTIAL FOR STRONG
WINDS/BLOWING SNOW/FREEZING DRIZZLE/LIGHT SNOW ALL POSSIBLE ACROSS
THE NORTHWEST HALF OF THE CWA. THERE ARE JUST TOO MANY QUESTIONS
RIGHT NOW TO ZERO IN ON HOW THIS WILL EVOLVE...AND WHAT FLAVOR OF
HAZARD WE WILL NEED.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 233 AM MDT MON APR 8 2013
SOME DISAGREEMENT AND UNCERTAINTY THROUGH THIS PERIOD...ESPECIALLY
EARLY ON. IN GENERAL...DETERMINISTIC AND ENSEMBLE OUTPUT SUPPORT
A ZONAL OR NEARLY ZONAL FLOW THROUGH THIS PERIOD WITH MANY SMALL
SCALE SHORTWAVE TROUGHS MOVING THROUGH. MODELS HAVING TROUBLE
RESOLVING WHAT IS GOING TO HAPPEN IN THE SHORT TERM AND THAT HAS
AFFECTS INTO THIS PERIOD. MODELS DISAGREE ON THE FLOW ALOFT AND
SHORTWAVES IN THIS FLOW THROUGH THIS PERIOD. THE CRH_INIT HAS
GIVEN ME SOME SLIGHT CHANCE POPS THURSDAY NIGHT AND ONCE AGAIN
FROM FRIDAY NIGHT INTO SATURDAY MORNING. GIVEN THE PROBLEMS
DISCUSSED ABOVE AND SINCE ONLY SLIGHT CHANCE WILL NOT MAKE ANY
CHANGES TO THESE GRIDS. OTHERWISE LOOKS DRY FOR THE REST OF THE
PERIOD.
LEFT REMAINING GRIDS ALONE AS WELL. LOOKS LIKE A WARMING TREND
OCCURS THROUGH THIS PERIOD AND THIS LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE
INITIATION...BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME
SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ003-004-
015-016-029.
CO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ090.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
243 AM MDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 233 PM MDT SUN APR 7 2013
LATER THIS AFTERNOON MODELS CONTINUE TO INDICATE MUCAPE AROUND
500J/KG OR SO JUST EAST OF A SURFACE TROUGH EAST OF A GOVE TO HILL
CITY LINE. 0-6KM SHEAR OF 40 KTS WILL BE FAVORABLE FOR STRONG/SEVERE
STORMS TO DEVELOP...HOWEVER THERE WILL BE SOME SUBSIDENCE
INTERSPERCED WITH LIFT BEHIND THE EXITING SHORT WAVE TROUGH. IF
SEVERE THUNDERSTORMS DO DEVELOP...AM ANTICIPATING THEM TO BE ONLY
ISOLATED WITH HAIL UP TO QUARTER SIZE AND GUSTY OUTFLOW WINDS. THE
STRONG/SEVERE ACTIVITY SHOULD QUICKLY DIMINISH DURING THE EARLY
EVENING AS THE ENVIRONMENT BECOMES MORE STABLE.
TONIGHT SOME LINGERING LIFT BEHIND THE UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE INTO THE AREA THIS EVENING FROM THE WEST...WITH SOME LIFT
OVER THE FAR EASTERN PART OF THE AREA AS WELL. THE LIFT WILL MOVE
THROUGH THE AREA AND WEAKEN DURING THE LATE EVENING. DUE TO THE DRY
ENVIRONMENT BELOW 700MB OR SO...AND SUBTLE NATURE OF THE LIFT WILL
ONLY HAVE SLIGHT CHANCES FOR PRECIP. OVERNIGHT SUBSIDENCE AND DRIER
AIR MOVE INTO THE AREA BRINGING ANY PRECIP. TO AN END.
MONDAY AM ANTICIPATING ELEVATED THUNDERSTORMS TO BEGIN OVER EAST
CENTRAL COLORADO DURING THE EARLY AFTERNOON AS LIFT FROM A SHORT
WAVE TROUGH OVERSPREADS THE AREA. SOUNDINGS DURING THE EARLY
AFTERNOON REMAIN FAIRLY DRY UNTIL MOISTURE ADVECTION INCREASES WITH
STRENGTHENING LOW LEVEL JET DURING THE MID AND LATE AFTERNOON...SO
HAVE SLOWED HOW QUICKLY PRECIP. CHANCES INCREASE DURING THE
AFTERNOON. A WARM FRONT WILL MOVE INTO THE AREA DURING THE LATE
MORNING AND AFTERNOON. MODELS GENERALLY PLACE THE WARM FRONT BETWEEN
HWY 24 AND THE NEBRASKA BORDER. THE POSITION OF THE DRY LINE IS A
BIT HARDER TO PLACE...WITH MODELS EITHER KEEPING IT ALONG THE KS/CO
BORDER OR FURTHER EAST INTO WEST CENTRAL/SOUTHWEST KANSAS. THE
SREF/ECMWF/GFS GENERALLY PLACE IT ALONG THE KS/CO BORDER...SO WILL
SIDE WITH THEM. THIS PLACES THE INTERSECTION OF THE DRY LINE/WARM
FRONT NEAR THE CENTRAL PART OF THE TRI-STATE AREA. AM THINKING THE
STRONGER STORMS SHOULD BEGIN TO INITIATE TOWARD EARLY/MID AFTERNOON
NEAR THE INTERSECTION AS THE MOISTURE ADVECTION INCREASES
INSTABILITY. NAM POINT SOUNDINGS SHOW SLIGHTLY MORE INSTABILITY
ALONG THE DRY LINE THAN THE WARM FRONT. IN ADDITION MORE LIFT WILL
BE ALONG THE DRY LINE THAN THE WARM FRONT...SO AM THINKING STORMS SHOULD
FIRE ALONG THE DRY LINE FIRST THEN THE WARM FRONT. AS THE AFTERNOON
PROGRESSES THE WARM FRONT WILL ARK TO THE NORTHWEST...CAUSING THE
ENVIRONMENT TO BECOME MORE UNSTABLE OVER THE NORTHERN PART OF THE
AREA. THUNDERSTORM COVERAGE WILL INCREASE DURING THE MID TO LATE
AFTERNOON AS CAPE AND SYNOPTIC LIFT INCREASE OVER THE AREA.
DURING THE LATE AFTERNOON THE ENVIRONMENT SOUTH AND EAST OF HWY 40
BECOMES INCREASINGLY FAVORABLE FOR TON ADO DEVELOPMENT WITH 0-1KM
BULK SHEAR AROUND 15KTS AND EHI OF 3.5M2/S2. THE LARGE HAIL THREAT
LOOKS VERY GOOD...ESPECIALLY DURING THE MID TO LATE AFTERNOON AS THE
CAPE PROFILE IN THE HAIL GROWTH ZONE INCREASES AND MUCAPE NEARS
2000-3000J/KG.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 233 AM MDT MON APR 8 2013
SOME DISAGREEMENT AND UNCERTAINTY THROUGH THIS PERIOD...ESPECIALLY EARLY
ON. IN GENERAL...DETERMINISTIC AND ENSEMBLE OUTPUT SUPPORT A ZONAL OR
NEARLY ZONAL FLOW THROUGH THIS PERIOD WITH MANY SMALL SCALE SHORTWAVE
TROUGHS MOVING THROUGH. MODELS HAVING TROUBLE RESOLVING WHAT IS GOING
TO HAPPEN IN THE SHORT TERM AND THAT HAS AFFECTS INTO THIS PERIOD.
MODELS DISAGREE ON THE FLOW ALOFT AND SHORTWAVES IN THIS FLOW
THROUGH THIS PERIOD. THE CRH_INIT HAS GIVEN ME SOME SLIGHT CHANCE
POPS THURSDAY NIGHT AND ONCE AGAIN FROM FRIDAY NIGHT INTO SATURDAY
MORNING. GIVEN THE PROBLEMS DISCUSSED ABOVE AND SINCE ONLY SLIGHT
CHANCE WILL NOT MAKE ANY CHANGES TO THESE GRIDS. OTHERWISE LOOKS
DRY FOR THE REST OF THE PERIOD.
LEFT REMAINING GRIDS ALONE AS WELL. LOOKS LIKE A WARMING TREND
OCCURS THROUGH THIS PERIOD AND THIS LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE INITIATION...
BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ090.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...BULLER
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
116 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 110 AM CDT MON APR 8 2013
THE TAIL END OF A LINE OF STORMS HAS MOVED EAST OUT OF THE CWA. A
FEW SHOWERS MAY DEVELOP NORTH OF AN OUTFLOW BOUNDARY THAT EXTENDS
FROM NEAR EUDORA...SOUTHWEST TO CARBONDALE. HOWEVER AS 925MB TO
850MB WINDS CONTINUE TO VEER THE ISENTROPIC LIFT NORTH OF THIS
BOUNDARY WILL WEAKEN AFTER 9Z. UPDATED ZONES TO REDUCE POPS TO
AREAS OF EAST CENTRAL KS SOUTH OF THE KS TURNPIKE...AND THEN
REDUCED POPS TO OR BELOW 14 PERCENT AFTER 9Z.
GARGAN
UPDATE ISSUED AT 959 PM CDT SUN APR 7 2013
UPDATED POPS/WX TO REFLECT THE LATEST RADAR TRENDS WITH THIS
EVENING`S THUNDERSTORM ACTIVITY. THUNDERSTORMS HAVE BEEN STEADILY
WEAKENING OVER THE LAST HOUR AND DIMINISHING IN COVERAGE ACROSS THE
FORECAST AREA. AS OF 03Z...THE LAST BAND OF THUNDERSTORMS WAS
TRACKING EAST ACROSS NORTHEASTERN KANSAS...HOWEVER A FEW ISOLATED
THUNDERSTORMS MAY STILL DEVELOP ACROSS EAST CENTRAL KANSAS THROUGH
LATE THIS EVENING. THESE LINGERING THUNDERSTORMS ARE ANTICIPATED TO
PROGRESS EAST OF THE CWA BY AROUND 06Z. AS A RESULT...HAVE TRENDED
WITH LOWERING POPS FROM WEST TO EAST ACROSS THE CWA THROUGH THE
REMAINDER OF THIS EVENING INTO THE EARLY OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
19Z WATER VAPOR IMAGERY SHOWS A QUASI-ZONAL FLOW ACROSS THE PLAINS
WITH A LOW AMPLITUDE SHORTWAVE MOVING ACROSS THE CO AND NM ROCKIES.
AT THE SURFACE A TROUGH OF LOW PRESSURE IN THE LEE OF THE ROCKIES
HAS STRENGTHENED AND CAUSED SOUTH AND SOUTHEAST WINDS TO INCREASE
BRINGING BETTER MOISTURE NORTH INTO SOUTHERN AND EASTERN KS.
THE UPPER WAVE IS EXPECTED TO MOVE ACROSS THE STATE THIS
EVENING...AND TRIGGER ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL KS. THIS ACTIVITY SHOULD MOVE ACROSS NORTHEAST KS THROUGH
THE EVENING. 18Z RUC SHOWS THE BETTER INSTABILITY CURRENTLY OVER
SOUTHERN KS WHERE THE DEWPOINTS ARE IN THE UPPER 50S. AS THE
SOUTHERLY WINDS CONTINUE TO BRING THE MOISTURE AND INSTABILITY INTO
EAST CENTRAL KS...THERE IS THE POTENTIAL THAT ANY CONVECTION IN
SOUTH CENTRAL KS COULD MOVE INTO THE AREA AND REMAIN ORGANIZED
ENOUGH FOR A SEVERE THREAT. PERHAPS THE GREATER THREAT FOR SEVERE
WEATHER MAY COME FROM ANY THUNDERSTORM DEVELOPMENT IN CENTRAL KS
THAT MOVES IN FROM THE WEST THIS EVENING. MODELS SHOW LOW LEVEL
SHEER INCREASING AS THE LOW LEVEL JET INCREASES. HOWEVER THE RAP
CONTINUES TO SHOW THE BEST INSTABILITY REMAINING ACROSS CENTRAL AND
SOUTHERN KS AND ALONG THE SOUTHWESTERN EDGE OF THE FORECAST AREA.
THERE COULD BE A SHORT WINDOW FOR SEVERE WEATHER IF DISCRETE STORMS
WERE ABLE TO FORM AND MOVE INTO THE AREA. GIVEN THE INCREASING 0-1KM
SHEER PARAMETERS...A TORNADO CAN NOT BE RULED OUT EITHER. EVENTUALLY
STORMS SHOULD BECOME MORE ELEVATED WITH CELL MERGERS DISRUPTING
UPDRAFT ORGANIZATION.
THINK THAT AS THE UPPER LEVEL WAVE PASSES EAST AROUND
MIDNIGHT...PRECIP CHANCES WILL QUICKLY DIMINISH OVERNIGHT. OVERNIGHT
LOWS SHOULD BE PRETTY MILD WITH CONTINUED SOUTH WINDS AND MOSTLY
CLOUDY SKIES PREVENTING MUCH IN THE WAY OF RADIATIONAL COOLING. SOME
OF THE OBJECTIVE GUIDANCE HAS LOW STRATUS MOVING IN WITH CONTINUED
MOISTURE ADVECTION FROM THE SOUTH. THEREFORE KEPT AT LEAST MOSTLY
CLOUDY SKIES IN THE FORECAST FOR TONIGHT.
FOR MONDAY FORECAST SOUNDINGS SHOW AN ELEVATED MIXED LAYER MOVING
OVER THE FORECAST AREA WITH LITTLE IN THE WAY OF LARGE SCALE FORCING
OR SURFACE BASED LIFT. BECAUSE OF THIS HAVE REMOVED POPS FOR MUCH OF
THE DAY THINKING THE BOUNDARY LAYER WILL REMAIN CAPPED. THE FORECAST
DOES SHOW CHANCES BEGINNING TO INCREASE LATE IN THE DAY AS DAY TIME
HEATING COULD CAUSE THE CAP TO WEAKEN ACROSS NORTH CENTRAL KS.
DEPENDING ON WHETHER THE LOW CLOUDS DEVELOP OR NOT...HIGHS SHOULD
MAKE IT INTO THE 70S. DID LOWER HIGHS A COUPLE DEGREES ACROSS EAST
CENTRAL KS WHERE CLOUDS ARE EXPECTED TO PERSIST LONGER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
BY THE EVENING HOURS ON MONDAY...A CONSIDERABLE EML MOVES OVER THE
MAJORITY OF THE CWA. HAVE BACKED OFF ON POPS AS A RESULT ALONG AND
SOUTH OF I70...AND MAY NEED TO BACK OFF EVEN MORE. TO THE
NORTH...THE CAP IS MUCH WEAKER...AND WOULD ANTICIPATE THAT BY
SUNRISE THERE WILL BE ENOUGH LIFT FROM THE LEADING WAVE AS WELL
AS CONVERGENCE IN THE LLJ AND THE SURFACE TROF FOR A LINE OF
THUNDERSTORMS ALONG THE KS NEBRASKA BORDER. COLD FRONT TO THE WEST
IS CONCURRENTLY SURGING TO THE SOUTHEAST AND MAY IMPINGE ON THE
FAR NW CORNER OF THE CWA BY AROUND 12Z TUESDAY...AND WILL CARRY
HIGHEST POPS TO THE NW.
CONDITIONS BY 12Z TUESDAY WILL BE IMPACTED BY PREVIOUS NIGHTS
WEATHER...BUT STILL APPEARS THAT LATE MORNING INTO THE EVENING
HOURS WILL BE THE GREATEST RISK FOR OUR FORECAST AREA FOR STRONG
TO SEVERE STORMS. THE DRYLINE AND FRONT COME TOGETHER OUT IN
WESTERN KANSAS IN THE MORNING AND BOTH MERGE AND MOVE INTO THE
WESTERN COUNTIES BY EARLY AFTERNOON. EC AND GFS SLIGHTLY SLOWER
AND COULD ALLOW FOR A BIT MORE BUILDUP OF INSTABILITY ACROSS THE
EAST BEFORE THE FRONT SURGES THROUGH LATE DAY. WITH WINDS THROUGH
THE COLUMN NEARLY RUNNING PARALLEL TO THE FRONT...DISCRETE CELLS
THAT INITIALLY FORM MAY EVOLVE QUICKLY INTO A LINE THAT ADVANCES
ACROSS THE CWA THROUGH THE EVENING HOURS. THIS WOULD MAKE SEVERE
WINDS THE PRIMARY CONCERN...ALTHOUGH WITH A QUICK INCREASE IN WIND
SPEEDS IN THE LOW LEVELS AND GOOD LOW LEVEL HELICITY CANT RULE OUT
ISOLATED TORNADOES...ESP IN EARLY ONSET OF THE CONVECTION AND IN
ANY STORMS THAT CAN FORM OUT IN THE WARM SECTOR.
TUESDAY NIGHT THROUGH FRIDAY BRING AN UNSEASONABLY COOL PERIOD AS
THE UPPER LOW CONTINUES TO DRAW COLDER AIR INTO THE PLAINS THROUGH
THE END OF THE WEEK. DAYTIME HIGHS WED WILL STRUGGLE TO REACH 40S
WHILE THURS AND FRI MAKE A SLOW CLIMB INTO THE MIDDLE 50S. BY THE
WEEKEND SOUTHERLY FLOW AT THE SURFACE AND WESTERLY FLOW ALOFT
BRING TEMPERATURES BACK TOWARD NORMAL WITH SOME CHANCES FOR RAIN
WITH SOME WEAK WAVES IN THE FLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1217 AM CDT MON APR 8 2013
FOR THE 06Z TAFS...THE REMNANTS OF THIS EVENING`S THUNDERSTORM
ACTIVITY WAS MOVING EAST OF THE AREA. THERE STILL MAY BE A FEW
VICINITY SHOWERS AND THUNDERSTORMS AROUND 06Z...BUT THESE SHOULD
QUICKLY MOVE EAST. MVFR CIGS/VIS EXPECTED THROUGH THE EARLY
OVERNIGHT HOURS...HOWEVER MODELS CONTINUE TO SHOW CIGS DROPPING DOWN
TO IFR CONDITIONS FOR A FEW HOURS THROUGH SUNRISE AND POSSIBLY
PERSIST INTO THE MID MORNING HOURS BEFORE LIFTING BACK TO MVFR
CONDITIONS. THE NAM IS SET ON KEEPING THE TAF SITES STUCK IN MVFR
CIGS THROUGH THE AFTERNOON WITH THE GFS SUGGESTING A FEW HOURS VFR
CONDITIONS POSSIBLE. THERE IS STILL UNCERTAINTY REGARDING THE
POTENTIAL FOR SOME SHOWERS AND THUNDERSTORMS TO DEVELOP LATER THIS
EVENING...BUT MODELS DO AGREE IN HAVING MVFR CIGS IN PLACE TOWARD
THE END OF THE TAF PERIOD.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1219 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 959 PM CDT SUN APR 7 2013
UPDATED POPS/WX TO REFLECT THE LATEST RADAR TRENDS WITH THIS
EVENING`S THUNDERSTORM ACTIVITY. THUNDERSTORMS HAVE BEEN STEADILY
WEAKENING OVER THE LAST HOUR AND DIMINISHING IN COVERAGE ACROSS THE
FORECAST AREA. AS OF 03Z...THE LAST BAND OF THUNDERSTORMS WAS
TRACKING EAST ACROSS NORTHEASTERN KANSAS...HOWEVER A FEW ISOLATED
THUNDERSTORMS MAY STILL DEVELOP ACROSS EAST CENTRAL KANSAS THROUGH
LATE THIS EVENING. THESE LINGERING THUNDERSTORMS ARE ANTICIPATED TO
PROGRESS EAST OF THE CWA BY AROUND 06Z. AS A RESULT...HAVE TRENDED
WITH LOWERING POPS FROM WEST TO EAST ACROSS THE CWA THROUGH THE
REMAINDER OF THIS EVENING INTO THE EARLY OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
19Z WATER VAPOR IMAGERY SHOWS A QUASI-ZONAL FLOW ACROSS THE PLAINS
WITH A LOW AMPLITUDE SHORTWAVE MOVING ACROSS THE CO AND NM ROCKIES.
AT THE SURFACE A TROUGH OF LOW PRESSURE IN THE LEE OF THE ROCKIES
HAS STRENGTHENED AND CAUSED SOUTH AND SOUTHEAST WINDS TO INCREASE
BRINGING BETTER MOISTURE NORTH INTO SOUTHERN AND EASTERN KS.
THE UPPER WAVE IS EXPECTED TO MOVE ACROSS THE STATE THIS
EVENING...AND TRIGGER ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL KS. THIS ACTIVITY SHOULD MOVE ACROSS NORTHEAST KS THROUGH
THE EVENING. 18Z RUC SHOWS THE BETTER INSTABILITY CURRENTLY OVER
SOUTHERN KS WHERE THE DEWPOINTS ARE IN THE UPPER 50S. AS THE
SOUTHERLY WINDS CONTINUE TO BRING THE MOISTURE AND INSTABILITY INTO
EAST CENTRAL KS...THERE IS THE POTENTIAL THAT ANY CONVECTION IN
SOUTH CENTRAL KS COULD MOVE INTO THE AREA AND REMAIN ORGANIZED
ENOUGH FOR A SEVERE THREAT. PERHAPS THE GREATER THREAT FOR SEVERE
WEATHER MAY COME FROM ANY THUNDERSTORM DEVELOPMENT IN CENTRAL KS
THAT MOVES IN FROM THE WEST THIS EVENING. MODELS SHOW LOW LEVEL
SHEER INCREASING AS THE LOW LEVEL JET INCREASES. HOWEVER THE RAP
CONTINUES TO SHOW THE BEST INSTABILITY REMAINING ACROSS CENTRAL AND
SOUTHERN KS AND ALONG THE SOUTHWESTERN EDGE OF THE FORECAST AREA.
THERE COULD BE A SHORT WINDOW FOR SEVERE WEATHER IF DISCRETE STORMS
WERE ABLE TO FORM AND MOVE INTO THE AREA. GIVEN THE INCREASING 0-1KM
SHEER PARAMETERS...A TORNADO CAN NOT BE RULED OUT EITHER. EVENTUALLY
STORMS SHOULD BECOME MORE ELEVATED WITH CELL MERGERS DISRUPTING
UPDRAFT ORGANIZATION.
THINK THAT AS THE UPPER LEVEL WAVE PASSES EAST AROUND
MIDNIGHT...PRECIP CHANCES WILL QUICKLY DIMINISH OVERNIGHT. OVERNIGHT
LOWS SHOULD BE PRETTY MILD WITH CONTINUED SOUTH WINDS AND MOSTLY
CLOUDY SKIES PREVENTING MUCH IN THE WAY OF RADIATIONAL COOLING. SOME
OF THE OBJECTIVE GUIDANCE HAS LOW STRATUS MOVING IN WITH CONTINUED
MOISTURE ADVECTION FROM THE SOUTH. THEREFORE KEPT AT LEAST MOSTLY
CLOUDY SKIES IN THE FORECAST FOR TONIGHT.
FOR MONDAY FORECAST SOUNDINGS SHOW AN ELEVATED MIXED LAYER MOVING
OVER THE FORECAST AREA WITH LITTLE IN THE WAY OF LARGE SCALE FORCING
OR SURFACE BASED LIFT. BECAUSE OF THIS HAVE REMOVED POPS FOR MUCH OF
THE DAY THINKING THE BOUNDARY LAYER WILL REMAIN CAPPED. THE FORECAST
DOES SHOW CHANCES BEGINNING TO INCREASE LATE IN THE DAY AS DAY TIME
HEATING COULD CAUSE THE CAP TO WEAKEN ACROSS NORTH CENTRAL KS.
DEPENDING ON WHETHER THE LOW CLOUDS DEVELOP OR NOT...HIGHS SHOULD
MAKE IT INTO THE 70S. DID LOWER HIGHS A COUPLE DEGREES ACROSS EAST
CENTRAL KS WHERE CLOUDS ARE EXPECTED TO PERSIST LONGER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
BY THE EVENING HOURS ON MONDAY...A CONSIDERABLE EML MOVES OVER THE
MAJORITY OF THE CWA. HAVE BACKED OFF ON POPS AS A RESULT ALONG AND
SOUTH OF I70...AND MAY NEED TO BACK OFF EVEN MORE. TO THE
NORTH...THE CAP IS MUCH WEAKER...AND WOULD ANTICIPATE THAT BY
SUNRISE THERE WILL BE ENOUGH LIFT FROM THE LEADING WAVE AS WELL
AS CONVERGENCE IN THE LLJ AND THE SURFACE TROF FOR A LINE OF
THUNDERSTORMS ALONG THE KS NEBRASKA BORDER. COLD FRONT TO THE WEST
IS CONCURRENTLY SURGING TO THE SOUTHEAST AND MAY IMPINGE ON THE
FAR NW CORNER OF THE CWA BY AROUND 12Z TUESDAY...AND WILL CARRY
HIGHEST POPS TO THE NW.
CONDITIONS BY 12Z TUESDAY WILL BE IMPACTED BY PREVIOUS NIGHTS
WEATHER...BUT STILL APPEARS THAT LATE MORNING INTO THE EVENING
HOURS WILL BE THE GREATEST RISK FOR OUR FORECAST AREA FOR STRONG
TO SEVERE STORMS. THE DRYLINE AND FRONT COME TOGETHER OUT IN
WESTERN KANSAS IN THE MORNING AND BOTH MERGE AND MOVE INTO THE
WESTERN COUNTIES BY EARLY AFTERNOON. EC AND GFS SLIGHTLY SLOWER
AND COULD ALLOW FOR A BIT MORE BUILDUP OF INSTABILITY ACROSS THE
EAST BEFORE THE FRONT SURGES THROUGH LATE DAY. WITH WINDS THROUGH
THE COLUMN NEARLY RUNNING PARALLEL TO THE FRONT...DISCRETE CELLS
THAT INITIALLY FORM MAY EVOLVE QUICKLY INTO A LINE THAT ADVANCES
ACROSS THE CWA THROUGH THE EVENING HOURS. THIS WOULD MAKE SEVERE
WINDS THE PRIMARY CONCERN...ALTHOUGH WITH A QUICK INCREASE IN WIND
SPEEDS IN THE LOW LEVELS AND GOOD LOW LEVEL HELICITY CANT RULE OUT
ISOLATED TORNADOES...ESP IN EARLY ONSET OF THE CONVECTION AND IN
ANY STORMS THAT CAN FORM OUT IN THE WARM SECTOR.
TUESDAY NIGHT THROUGH FRIDAY BRING AN UNSEASONABLY COOL PERIOD AS
THE UPPER LOW CONTINUES TO DRAW COLDER AIR INTO THE PLAINS THROUGH
THE END OF THE WEEK. DAYTIME HIGHS WED WILL STRUGGLE TO REACH 40S
WHILE THURS AND FRI MAKE A SLOW CLIMB INTO THE MIDDLE 50S. BY THE
WEEKEND SOUTHERLY FLOW AT THE SURFACE AND WESTERLY FLOW ALOFT
BRING TEMPERATURES BACK TOWARD NORMAL WITH SOME CHANCES FOR RAIN
WITH SOME WEAK WAVES IN THE FLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1217 AM CDT MON APR 8 2013
FOR THE 06Z TAFS...THE REMNANTS OF THIS EVENING`S THUNDERSTORM
ACTIVITY WAS MOVING EAST OF THE AREA. THERE STILL MAY BE A FEW
VICINITY SHOWERS AND THUNDERSTORMS AROUND 06Z...BUT THESE SHOULD
QUICKLY MOVE EAST. MVFR CIGS/VIS EXPECTED THROUGH THE EARLY
OVERNIGHT HOURS...HOWEVER MODELS CONTINUE TO SHOW CIGS DROPPING DOWN
TO IFR CONDITIONS FOR A FEW HOURS THROUGH SUNRISE AND POSSIBLY
PERSIST INTO THE MID MORNING HOURS BEFORE LIFTING BACK TO MVFR
CONDITIONS. THE NAM IS SET ON KEEPING THE TAF SITES STUCK IN MVFR
CIGS THROUGH THE AFTERNOON WITH THE GFS SUGGESTING A FEW HOURS VFR
CONDITIONS POSSIBLE. THERE IS STILL UNCERTAINTY REGARDING THE
POTENTIAL FOR SOME SHOWERS AND THUNDERSTORMS TO DEVELOP LATER THIS
EVENING...BUT MODELS DO AGREE IN HAVING MVFR CIGS IN PLACE TOWARD
THE END OF THE TAF PERIOD.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HENNECKE
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1112 PM MDT SUN APR 7 2013
.UPDATE...
ISSUED AT 956 PM MDT SUN APR 7 2013
INCREASED DEW POINTS TONIGHT...ESPECIALLY IN THE EASTERN THIRD OF
THE FORECAST AREA...GIVEN LATEST MODEL GUIDANCE AND SURFACE
ANALYSIS. ADDED SOME PATCHY FOG EAST OF HIGHWAY 83 WHERE DEW POINT
DEPRESSIONS WILL BE NEAR ZERO.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 233 PM MDT SUN APR 7 2013
LATER THIS AFTERNOON MODELS CONTINUE TO INDICATE MUCAPE AROUND
500J/KG OR SO JUST EAST OF A SURFACE TROUGH EAST OF A GOVE TO HILL
CITY LINE. 0-6KM SHEAR OF 40 KTS WILL BE FAVORABLE FOR STRONG/SEVERE
STORMS TO DEVELOP...HOWEVER THERE WILL BE SOME SUBSIDENCE
INTERSPERCED WITH LIFT BEHIND THE EXITING SHORT WAVE TROUGH. IF
SEVERE THUNDERSTORMS DO DEVELOP...AM ANTICIPATING THEM TO BE ONLY
ISOLATED WITH HAIL UP TO QUARTER SIZE AND GUSTY OUTFLOW WINDS. THE
STRONG/SEVERE ACTIVITY SHOULD QUICKLY DIMINISH DURING THE EARLY
EVENING AS THE ENVIRONMENT BECOMES MORE STABLE.
TONIGHT SOME LINGERING LIFT BEHIND THE UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE INTO THE AREA THIS EVENING FROM THE WEST...WITH SOME LIFT
OVER THE FAR EASTERN PART OF THE AREA AS WELL. THE LIFT WILL MOVE
THROUGH THE AREA AND WEAKEN DURING THE LATE EVENING. DUE TO THE DRY
ENVIRONMENT BELOW 700MB OR SO...AND SUBTLE NATURE OF THE LIFT WILL
ONLY HAVE SLIGHT CHANCES FOR PRECIP. OVERNIGHT SUBSIDENCE AND DRIER
AIR MOVE INTO THE AREA BRINGING ANY PRECIP. TO AN END.
MONDAY AM ANTICIPATING ELEVATED THUNDERSTORMS TO BEGIN OVER EAST
CENTRAL COLORADO DURING THE EARLY AFTERNOON AS LIFT FROM A SHORT
WAVE TROUGH OVERSPREADS THE AREA. SOUNDINGS DURING THE EARLY
AFTERNOON REMAIN FAIRLY DRY UNTIL MOISTURE ADVECTION INCREASES WITH
STRENGTHENING LOW LEVEL JET DURING THE MID AND LATE AFTERNOON...SO
HAVE SLOWED HOW QUICKLY PRECIP. CHANCES INCREASE DURING THE
AFTERNOON. A WARM FRONT WILL MOVE INTO THE AREA DURING THE LATE
MORNING AND AFTERNOON. MODELS GENERALLY PLACE THE WARM FRONT BETWEEN
HWY 24 AND THE NEBRASKA BORDER. THE POSITION OF THE DRY LINE IS A
BIT HARDER TO PLACE...WITH MODELS EITHER KEEPING IT ALONG THE KS/CO
BORDER OR FURTHER EAST INTO WEST CENTRAL/SOUTHWEST KANSAS. THE
SREF/ECMWF/GFS GENERALLY PLACE IT ALONG THE KS/CO BORDER...SO WILL
SIDE WITH THEM. THIS PLACES THE INTERSECTION OF THE DRY LINE/WARM
FRONT NEAR THE CENTRAL PART OF THE TRI-STATE AREA. AM THINKING THE
STRONGER STORMS SHOULD BEGIN TO INITIATE TOWARD EARLY/MID AFTERNOON
NEAR THE INTERSECTION AS THE MOISTURE ADVECTION INCREASES
INSTABILITY. NAM POINT SOUNDINGS SHOW SLIGHTLY MORE INSTABILITY
ALONG THE DRY LINE THAN THE WARM FRONT. IN ADDITION MORE LIFT WILL
BE ALONG THE DRY LINE THAN THE WARM FRONT...SO AM THINKING STORMS SHOULD
FIRE ALONG THE DRY LINE FIRST THEN THE WARM FRONT. AS THE AFTERNOON
PROGRESSES THE WARM FRONT WILL ARK TO THE NORTHWEST...CAUSING THE
ENVIRONMENT TO BECOME MORE UNSTABLE OVER THE NORTHERN PART OF THE
AREA. THUNDERSTORM COVERAGE WILL INCREASE DURING THE MID TO LATE
AFTERNOON AS CAPE AND SYNOPTIC LIFT INCREASE OVER THE AREA.
DURING THE LATE AFTERNOON THE ENVIRONMENT SOUTH AND EAST OF HWY 40
BECOMES INCREASINGLY FAVORABLE FOR TON ADO DEVELOPMENT WITH 0-1KM
BULK SHEAR AROUND 15KTS AND EHI OF 3.5M2/S2. THE LARGE HAIL THREAT
LOOKS VERY GOOD...ESPECIALLY DURING THE MID TO LATE AFTERNOON AS THE
CAPE PROFILE IN THE HAIL GROWTH ZONE INCREASES AND MUCAPE NEARS
2000-3000J/KG.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 233 PM MDT SUN APR 7 2013
UPPER FLOW WILL BE SOUTHWEST MONDAY NIGHT AHEAD OF AN UPPER LOW THAT
WILL MOVE INTO COLORADO TUESDAY. THE UPPER LOW WILL MOVE INTO
SOUTHWEST NEBRASKA TUESDAY NIGHT AND GRADUALLY SHIFT EAST INTO SOUTH
CENTRAL NEBRASKA WEDNESDAY. SURFACE LOW PRESSURE WILL MOVE INTO
SOUTHEAST COLORADO MONDAY NIGHT AND THEN MOVE EAST INTO SOUTH
CENTRAL KANSAS TUESDAY. A COLD FRONT WILL MOVE INTO EASTERN COLORADO
TUESDAY. THIS FRONT WILL PUSH ACROSS THE ENTIRE FA BY 18Z TUESDAY.
SURFACE WINDS SHOULD RANGE FROM 25 TO 35 KTS. HIGH PRESSURE WILL
CONTINUE TO BUILD INTO THE CENTRAL PLAINS WEDNESDAY. WIND WILL NOT
BE AS STRONG ON WEDNESDAY.
FOR MONDAY NIGHT...FOR EARLY EVENING...A SHORTWAVE COMES THROUGH
WITH MOISTURE AND GOOD LIFT EAST OF THE COLORADO LINE. CAPE VALUES
WILL RANGE FROM 700 J/KG IN EASTERN COLORADO TO 2500 NEAR HILL CITY.
BEST CAPE VALUES ARE GENERALLY EAST OF THE COLORADO STATE LINE AS
WELL. BY 03Z TUESDAY CONVECTIVE INHIBITION SHOULD TAKE OVER. AROUND
MIDNIGHT GOOD MOISTURE AND LIFT WILL MOVE INTO AN AREA GENERALLY
NORTH OF INTERSTATE 70. A COLD FRONT WILL ALSO MOVE INTO THE
NORTHWEST FA BRINGING COLDER AIR INTO THE REGION. PRECIPITATION WILL
CHANGE TO SNOW OVER THE FAR NORTHWEST FA. POPS WILL RANGE FROM
CHANCE IN THE SOUTH TO CATEGORICAL IN THE NORTHWEST.
TUESDAY...THE COLD FRONT WILL MOVE THROUGH THE REST OF THE FA BY 18Z
WITH SUSTAINED WIND AROUND 25KTS. THIS MAY REQUIRE A WIND ADVISORY.
GOOD MOISTURE AND LIFT WILL MOVE INTO THE NORTHWEST HALF OF THE FA
WITH THE FRONT. BY AFTERNOON, A DRY SLOT WILL MOVE INTO THE
SOUTHEAST FA. PRECIPITATION WILL CHANGE TO SNOW BEHIND THE FRONT
CAUSING SNOW TO SPREAD INTO NORTHWEST KANSAS AND SOUTHWEST NEBRASKA
TUESDAY MORNING. SNOW WILL CONTINUE TO SPREAD EAST ACROSS NORTHWEST
KANSAS DURING THE AFTERNOON. POPS WILL RANGE FROM CHANCE IN THE
SOUTH TO CATEGORICAL IN THE NORTH. PLAN TO CONTINUE THE WINTER
STORM WATCH FOR YUMA COUNTY WHERE TOTAL SNOWFALL WILL RANGE FROM 5
TO 6 INCHES IN THE NORTHWEST CORNER OF THE COUNTY. OTHERWISE
SNOWFALL AMOUNTS SHOULD RANGE FROM 1 TO 2 INCHES MAINLY ACROSS THE
NORTHWEST HALF OF THE FA WITH AMOUNTS LESS THAN AN INCH ACROSS THE
EAST.
TUESDAY NIGHT...THE DRY SLOT CONTINUES TO AFFECT THE SOUTHEAST ZONES
IN THE EVENING. THE BEST MOISTURE AND LIFT WILL BE CONFINED TO THE
FAR NORTHERN ZONES. LIFT CONTINUES TO MOVE NORTHWARD WITH THE LOW
THROUGH THE NIGHT. SUBSIDENCE IS OVER THE SOUTHERN FA AFTER
MIDNIGHT. POPS WILL DECREASE FROM LIKELY IN THE NORTH TO CHANCE WITH
CHANCE TO SLIGHT CHANCE POPS ELSEWHERE.
WEDNESDAY...DYNAMICS ARE WELL NORTH OF THE FA SO POPS WILL BE SLIGHT
CHANCE AND CHANCE MAINLY OVER THE NORTHEAST PORTION OF THE FA.
PRECIPITATION SHOULD END OTHER THAN SOME LIGHT PRECIPITATION IN THE
FAR NORTHEAST IN THE AFTERNOON.
MIN TEMPERATURES MONDAY NIGHT WILL VARY WIDELY FROM THE LOWER 20S IN
EASTERN COLORADO TO THE UPPER 40S IN THE EAST. MIN TEMPERATURES
TUESDAY NIGHT WILL BE IN THE MID TEENS TO THE LOWER 20S. MAX
TEMPERATURES TUESDAY WILL RANGE FROM THE MID 20S IN EASTERN COLORADO
TO NEAR 50 IN THE EAST. MAX TEMPERATURES WEDNESDAY WILL RISE INTO
THE MID/UPPER 30S.
IN THE EXTENDED...(WEDNESDAY NIGHT THROUGH SUNDAY)...UPPER FLOW
WILL BE NORTHWEST THROUGH THIS PERIOD. OTHER THAN A SLIGHT CHANCE
OF LIGHT RAIN AND SNOW SHOWERS THURSDAY NIGHT THE FORECAST SHOULD
BE DRY. ANOTHER WEAK WAVE COMES THROUGH THE FLOW SATURDAY NIGHT
BUT DYNAMICS ARE VERY WEAK. THERE WILL BE A SLIGHT CHANCE OF LIGHT
RAIN SHOWERS ACROSS THE FAR NORTH.
TEMPERATURES WEDNESDAY NIGHT WILL BE THE COLDEST WITH SNOW ON THE
GROUND. EXPECT LOW TEMPERATURES IN THE UPPER TEENS TO AROUND 20. LOW
TEMPERATURES WILL MODERATE TO THE LOWER 30S THURSDAY NIGHT AND INTO
THE UPPER 30S/LOWER 40S SUNDAY NIGHT. HIGH TEMPERATURES THURSDAY
WILL STRUGGLE TO RISE OUT OF THE 30S WITH SNOW ON THE GROUND. MAX
TEMPERATURES WILL MODERATE TO THE LOWER 50S FRIDAY AND INTO THE
UPPER 60S SATURDAY/SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE INITIATION...
BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WINTER STORM WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY
AFTERNOON FOR COZ090.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...JTL
LONG TERM...FS
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
429 AM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW PRESSURE
WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
NEAR TERM: EXPECT VFR CONDITIONS BY LATER THIS MORNING AND
CONTINUING VFR TONIGHT.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: FOR WINDS: HAVE BLENDED THE NAM12 AND GFS40 FOR
SUSTAIN WINDS AND WILL USE 125 PERCENT OF SUSTAINED WIND FOR GUST
SPEED. FOR WAVES: PRIMARY WAVE SYSTEM IS FROM SOUTH-SOUTHWEST WITH
SECONDARY LONGER PERIOD WAVE OUT OF SOUTHEAST. SINCE PRIMARY WAVE
GROUP WITH SOUTHWEST COMPONENT EXPECT WAVES TO SUBSIDE SHORTLY
AFTER WINDS LATER THIS MORNING SO 1500Z TIMING TO END SCA STILL
LOOKS GOOD.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
300 AM CDT MON APR 8 2013
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM CDT SUN APR 7 2013
FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH FORECAST AREA THIS
EVENING WITH INITIAL ACTIVITY DIMINISHING. MAIN FOCUS SHIFTS BACK
TO THE WEST AND NORTHWEST OF FORECAST AREA...WITH STORMS FIRING ON
NOSE OF LOW LEVEL JET. WILL SEE THIS ACTIVITY SLIDE NORTHEAST...
WITH KCOU REMAINING ON EASTERN FRINGES OF PCPN. WHILE KUIN...
SHOULD SEE PLENTY OF PCPN OVERNIGHT AS LOW LEVEL JET BEGINS TO
SHIFT TO A MORE SOUTHWESTERLY DIRECTION. VFR CIGS TO LOWER TO MVFR
WITH PCPN...BEFORE LIFTING AND SCATTERING OUT BY MID MORNING AS
RAIN COMES TO AN END. AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS
OVER THE NEXT SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF
TO VCSH MENTION BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR
THROUGH THE PERIOD. WINDS TO REMAIN FROM THE SOUTHEAST TO SOUTH
THROUGH THE FORECAST PERIOD.
SPECIFICS FOR KSTL...FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH
FORECAST AREA THIS EVENING WITH INITIAL ACTIVITY DIMINISHING.
MAIN FOCUS SHIFTS BACK TO THE WEST AND NORTHWEST OF FORECAST
AREA...WITH STORMS FIRING ON NOSE OF LOW LEVEL JET. WILL SEE THIS
ACTIVITY SLIDE NORTHEAST...AND REMAIN WELL NORTHWEST OF METRO AREA.
AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS OVER THE NEXT
SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF TO VCSH MENTION
BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR THROUGH THE PERIOD.
WINDS TO REMAIN FROM THE SOUTH THROUGH 13Z...BEFORE VEERING TO THE
SOUTHWEST THROUGH MIDDAY...THEN BACK TO THE SOUTH ONCE AGAIN.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1140 PM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 904 PM CDT SUN APR 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS BEEN ONGOING IN A NORTHWARD
LIFTING FRONTAL ZONE DRAPED ACROSS THE MIDSECTION OF THE CWA THIS
EVENING. LATEST RUC DATA ALONG WITH THE 4KM NSSL NMM WRF INDICATE
THE POTENTIAL FOR THE STORMS TO CONTINUE TO PERCOLATE IN THE
AFOREMENTIONED FRONTAL ZONE...WITH LOCALIZED MUCAPE VALUES AOA
200-400 J/KG. STORMS HAVE THUS FAR REMAINED SUB-SEVERE...HOWEVER
HAIL UP TO NICKEL SIZE HAS BEEN REPORTED WITH SOME OF THE STRONGER
STORMS OVER THE STL METRO EAST.
HAVE ADJUSTED TIMING OF PRECIPITATION THIS EVENING...ESPECIALLY
OVER THE WESTERN HALF OF THE CWA...WITH TWO MAIN AREAS OF CONCERN.
THE FIRST IS WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY THAT HAS
OVERSPREAD NW MO AND EASTERN KS THIS EVENING...EXPECTED TO MOVE
INTO CENTRAL AND NE MO THROUGH THE EARLY OVERNIGHT HOURS ON THE
NOSE OF AN INTENSIFYING LLJ. THE SECOND AREA OF CONCERN IS A
POTENT STORM MOVING THROUGH SOUTH CENTRAL MO WHICH HAS MAINTAINED
INTENSITY AS IT MARCHES EASTWARD. MODELS FORECAST THE STORM TO
WEAKEN PRIOR TO IMPACTING OUR SOUTHERN COUNTIES...THOUGH THE FACT
THAT IT HAS CONSISTENTLY PRODUCED GOLFBALL SIZED HAIL AND DOES NOT
APPEAR TO BE DIMINISHING IN STRENGTH HAS PIQUED OUR INTEREST A
BIT. MAY HAVE TO FURTHER ADJUST POPS OVER SOUTHERN COUNTIES IF
THIS STORM MAINTAINS ITS INTENSITY AND CURRENT TRACK. WILL
CONTINUE TO MONITOR THIS FEATURE CLOSELY.
OTHERWISE...THE FORECAST HAS REMAINED ON TRACK THIS
EVENING...WITH ONLY A FEW CHANGES TO TEMPERATURE AND DEWPOINT
TRENDS TO ACCOUNT FOR LOCATIONS WITH RAIN COOLED AIR DUE TO STORM
ACTIVITY TONIGHT.
JP
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 PM CDT SUN APR 7 2013
WHILE THE PRECIPITATION CHANCES ARE EXPECTED TO RAMP UP CONSIDERABLY
TONIGHT...THE EXACT DETAILS ARE STILL A TAD UNCLEAR. THIS IS IN
PART DUE TO DIFFERENCES AMONGST THE DETERMINISTIC MODELS AND
CONVECTION ALLOWING MODELS WITH RESPECT TO THE CONVECTIVE
EVOLUTION AND TIMING. THE OVERALL SCENARIO REMAINS UNCHANGED. A
QUASI-STATIONARY BOUNDARY NOW STRETCHES FROM NW MO THROUGH CENTRAL
MO WHERE IT THEN TAILS EASTWARD THRU THE ST LOUIS AREA INTO SE
ILLINOIS. MOISTURE ADVECTION TODAY AND HEATING HAS RESULTED IN A
WEAKLY UNSTABLE AIR MASS TO THE SOUTH OF THE BOUNDARY AND A GOOD
DEAL OF AGITATED CU IS NOW PRESENT. EVEN A FEW SPOTTY SHOWERS HAVE
DEVELOPED SSE OF ST LOUIS. THIS BOUNDARY IS FORECAST TO GRADUALLY
RETREAT NORTHWARD TONIGHT WHILE THE LOW AMPLITUDE SHORT WAVE NOW
OVER CENTRAL KS MOVES EASTWARD THRU THE AREA IN CONJUNCTION WITH
AN INTENSIFYING AND VEERING SWLY LLJ. ALL THE STRONG FORCING VIA
THE SHORTWAVE AND LLJ ARE FOCUSED ALONG AND NORTH OF I-70 WITHIN
THE COOL SECTOR NORTH OF THE RETREATING BOUNDARY. MY BEST GUESS IS
THAT THERE COULD BE SEVERAL WAVES OF ORGANIZED CONVECTION. THE
GROWING CONVECTION PRESENTLY IN SE KS MAY PUSH ENE INTO CENTRAL MO
THIS EVENING WHILE ADDITIONAL ISOLATED-SCATTERED CONVECTION COULD
ATTEMPT TO DEVELOP ALONG AND JUST SOUTH OF THE FRONT ZONE. THEN LATER
THIS EVENING AND TONIGHT ONE OR MORE CONVECTIVE CLUSTERS SHOULD
DEVELOP ACROSS NE KS AND NW MO AND MOVE EASTWARD IN CONJUNCTION
WITH THE VEERING LLJ AND MIGRATING SHORTWAVE TROF. WITH PLENTLY OF
DEEP LAYER SHEAR PRESENT...DEPENDING ON THE CAPE EVOLUTION...A FEW
OF THESE STORMS ACROSS CENTRAL MO COULD BE SEVERE.
I THINK BY DAYBREAK MONDAY...MOST OF THE OVERNIGHT CONVECTION
SHOULD BE NE OF THE CWA AS THE SHORTWAVE IS WELL TO THE EAST AND
THE LLJ IS STRONGLY VEERED TO THE WEST SOUTHWEST...HOWEVER I CANT
RULE OUT SOME SCATTERED TRAILING STORMS ALONG THE LLJ AXIS AND ANY
RESIDUAL BOUNDARIES. EVEN IF THIS IS PRESENT...I WOULD THINK IT
SHOULD HAVE EXITED THE AREA BY MID-LATE MORNING. THEREAFTER THE
EML BUILDS IN STRONGLY THROUGH THE AFTERNOON AND RESULTS IN
SUBSTANTIAL CAPPING OF THE WARM SECTOR...WITH THE FRONT LIFTING
INTO IOWA. THUS AFTERNOON THUNDERSTORM CHANCES LOOK MORE ISOLATED
BARING ANY LINGERING BOUNDARIES.
GLASS
.LONG TERM...(MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 244 PM CDT SUN APR 7 2013
THE LAST FEW DAYS THE ECMWF MODEL HAS BEEN AN OUTLIER WITH A MORE
SOUTHWARD EAST-WEST ORIENTED BOUNDARY POSITION ACROSS NORTHERN
MISSOURI FROM MONDAY THROUGH TUESDAY NIGHT. ON THE LAST 2 RUNS
HOWEVER THE ECMWF HAS JOINED THE REST OF THE MODELS WITH A MORE
NORTHWARD BOUNDARY POSITION ACROSS SOUTHERN IOWA OR THE MO/IA
BORDER. THIS WOULD SUGGEST LESSER PRECIPITATION CHANCES ACROSS
NORTHERN MISSOURI DUE TO THE LACK OF A FOCUSING BOUNDARY...AND AS
THE WARM SECTOR IS EXPECTED TO BE CHARACTERIZED BY A DECENT CAP
FOR SURFACE BASED STORMS UNTIL LATE TUESDAY NIGHT. THE MOST ACTIVE
PERIOD IS STILL EXPECTED TO BE THE LATE TUESDAY NIGHT INTO
WEDNESDAY TIME FRAME WHEN THE DEEP LARGE SCALE TROF AND ATTENDANT
COLD FRONT PROGRESSES EASTWARD INTO THE NATIONS MIDSECTION. I
STILL BELIEVE THE SCENARIO I LAYED OUT YESTERDAY IS QUITE
LIKELY... THAT THE ORGANIZED SEVERE CONVECTION ACROSS THE PLAINS
ON TUESDAY AFTERNOON WILL GROW UPSCALE INTO A LINE/QLCS AND SHIFT
EASTWARD INTO THE AREA OVERNIGHT TUESDAY INTO WEDNESDAY MORNING.
IT NOW APPEARS THAT ADDITIONAL STORMS COULD DEVELOP THROUGHOUT THE
DAY ON WEDNESDAY AND WED EVENING AHEAD OF THE COLD FRONT MOVING
ACROSS THE AREA...BUT THIS WILL BE LARGELY DEPENDENT ON STABILIZING
EFFECTS OF ANY PREVIOUS CONVECTION. STRONG DEEP LAYER SHEAR AND
AMPLE INSTABILITY SUPPORTS A SEVERE WEATHER THREAT PER THE SPC
OUTLOOKS.
IN THE WAKE OF THE MIDWEEK SYSTEM THERE WILL BE A GOOD COOL DOWN
THUR-FRIDAY TO BELOW AVERAGE TEMPS WITH BROAD CYCLONIC FLOW ALOFT
AND HIGH PRESSURE DOMINATING IN THE WAKE OF THE WEAKENING
PROGRESSIVE LONGWAVE TROF. THE FLOW ALOFT LOOKS TO TRANSITION TO
QUASI-ZONAL BY WEEKEND WITH THE SURFACE HIGH RETREATING...LEADING
TO MODERATING TEMPERATURES.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM CDT SUN APR 7 2013
FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH FORECAST AREA THIS
EVENING WITH INITIAL ACTIVITY DIMINISHING. MAIN FOCUS SHIFTS BACK
TO THE WEST AND NORTHWEST OF FORECAST AREA...WITH STORMS FIRING ON
NOSE OF LOW LEVEL JET. WILL SEE THIS ACTIVITY SLIDE NORTHEAST...
WITH KCOU REMAINING ON EASTERN FRINGES OF PCPN. WHILE KUIN...
SHOULD SEE PLENTY OF PCPN OVERNIGHT AS LOW LEVEL JET BEGINS TO
SHIFT TO A MORE SOUTHWESTERLY DIRECTION. VFR CIGS TO LOWER TO MVFR
WITH PCPN...BEFORE LIFTING AND SCATTERING OUT BY MID MORNING AS
RAIN COMES TO AN END. AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS
OVER THE NEXT SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF
TO VCSH MENTION BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR
THROUGH THE PERIOD. WINDS TO REMAIN FROM THE SOUTHEAST TO SOUTH
THROUGH THE FORECAST PERIOD.
SPECIFICS FOR KSTL...FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH
FORECAST AREA THIS EVENING WITH INITIAL ACTIVITY DIMINISHING.
MAIN FOCUS SHIFTS BACK TO THE WEST AND NORTHWEST OF FORECAST
AREA...WITH STORMS FIRING ON NOSE OF LOW LEVEL JET. WILL SEE THIS
ACTIVITY SLIDE NORTHEAST...AND REMAIN WELL NORTHWEST OF METRO AREA.
AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS OVER THE NEXT
SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF TO VCSH MENTION
BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR THROUGH THE PERIOD.
WINDS TO REMAIN FROM THE SOUTH THROUGH 13Z...BEFORE VEERING TO THE
SOUTHWEST THROUGH MIDDAY...THEN BACK TO THE SOUTH ONCE AGAIN.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BISMARCK ND
408 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 06 UTC TAF PERIOD. LATEST
SATELLITE IMAGERY HAS SHOWN LIFR TO IFR CONDITIONS IN STRATUS AND
FOG. LIFR TO IFR CEILINGS ARE EXPECTED TO CONTINUE THROUGH
DAYBREAK...AND THEN IMPROVE TO IFR TO MARGINAL MVFR.
LOW PRESSURE ACROSS MONTANA WILL DEVELOP AND SNOW WITH SLEET AND
FREEZING RAIN WILL BEGIN TO IMPACT KDIK AFTER 09Z...SPREADING EAST
MONDAY MORNING IMPACTING OTHER TERMINALS. VISIBILITIES IN SNOW AND
BLOWING SNOW WILL LIKELY FALL TO IFR AND BELOW FOR KDIK-KBIS.
SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON FOR ALL BUT
KJMS- KDIK AND POSSIBLY KBIS WHICH MAY REMAIN MVFR-IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ017>020-031>034-040>044.
&&
$$
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
107 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 107 AM CDT MON APR 8 2013
LATEST RADAR REFLECTIVITY AT 545Z SHOWS SOME LIGHT PRECIPITATION
STARTING TO DEVELOP ACROSS THE SOUTHWEST...WITH MORE WIDESPREAD
LIGHT TO MODERATE PRECIPITATION OVER EASTERN MONTANA EARLY THIS
MORNING. THE LATEST 04Z RAP HAS THE HEAVIER PRECIPITATION HOLDING
OFF UNTIL AFTER 08 TO 09Z. MEANWHILE ACROSS THEN NORTH...VERY
LIGHT RETURNS HAVE ALSO MANIFESTED...INDICATING SOME LIGHT SNOW
ALONG A COLD FRONT MOVING SOUTH FROM CANADA. SURFACE OBSERVATIONS
CONTINUE TO INDICATE THAT MOST OF THE SOUTHWEST REMAINS ABOVE
FREEZING...BUT ACROSS THE NORTH...TEMPERATURES HAVE RAPIDLY
COOLED. THIS TREND WILL CONTINUE AS COLDER AIR MOVES SOUTH.
OVERALL...DID NOT MAKE TOO MANY CHANGES TO ONGOING
FORECAST...OTHER THAN TO UPDATE FOR CURRENT OBS AND TRENDS.
THE MAIN FORECAST CHALLENGE WILL CONTINUE TO BE THE APPROACHING
SYSTEM AND WHETHER OR NOT ANY CHANGES TO ONGOING WINTER WEATHER
HEADLINES WILL BE NEEDED. WILL EVALUATE LATEST GFS AND WAIT FOR
THE 00Z ECWMF BEFORE MAKING ANY DECISIONS.
UPDATE ISSUED AT 1020 PM CDT SUN APR 7 2013
STORM SYSTEM SET TO IMPACT MONDAY MORNING/AFTERNOON WILL START TO
PRECIPITATE OVER MY FAR WEST AFTER MIDNIGHT...WITH THE HEAVIER
PRECIPITATION NOT TO ARRIVE UNTIL 09Z OR AFTER. AREA OF LIGHT SNOW
DEVELOPING ACROSS MY NORTH FROM CANADA WILL CONTINUE TO SLOWLY
MOVE SOUTH TO NEAR THE INTERSTATE 94 CORRIDOR OVERNIGHT ALONG A
SOUTHWARD ADVANCING COLD FRONT. OVERALL DID NOT MAKE MANY CHANGES
TO POPS FROM THE PREVIOUS UPDATED FORECAST. ADJUSTED TEMPERATURES
TO REFLECT LATEST OBS AND MODEL TRENDS...KEEPING THINGS WARM UNTIL
THE COLDER AIR MOVES IN FROM CANADA AFTER MIDNIGHT WITH EXTENSIVE
STRATUS IN PLACE.
OF NOTE TO THE MIDNIGHT SHIFT...THE 00Z NAM AND 18Z GFS HAVE COME
IN VERY WET WITH NEAR AN INCH OF QPF ALONG AND SOUTH OF THE
MISSOURI RIVER FOR STORM TOTALS OVERNIGHT THROUGH MONDAY
AFTERNOON. MUCH OF THIS LOOKS TO FALL AS SNOW. THE 12Z ECMWF WAS
ABOUT HALF AS WET. IF THE NAM/GFS VERIFY...WILL NEED TO UPGRADE
PARTS OF THE WINTER WEATHER ADVISORY TO A WARNING FOR HEAVY
SNOW...WITH AN INCH OF QPF RESULTING IN AT LEAST 10 INCHES OF
SNOW. WOULD ALSO HAVE TO CONSIDER EXPANDING THE AERIAL COVERAGE OF
THE WINTER WEATHER ADVISORY. WILL NEED TO SEE WHAT THE LATEST GFS
(00Z) COMES IN WITH...AND CHECK WITH THE WPC (WEATHER PREDICTION
CENTER) FOLKS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM CDT SUN APR 7 2013
FREEZING RAIN HAS ENDED NOW ACROSS THE JAMES RIVER VALLEY AS
TEMPERATURES HAVE WARMED ABOVE FREEZING. THE SNOW ACROSS THE NORTH
CENTRAL HAS ALSO ENDED. SO THERE IS A CLEAN SLATE FOR THE NEXT
WINTER SYSTEM WHICH IS FORECAST TO IMPACT MAINLY SOUTHWEST AND
SOUTH CENTRAL NORTH DAKOTA AFTER MIDNIGHT TONIGHT THROUGH MONDAY.
HAVE KEPT THE WINTER WEATHER ADVISORY FOR THIS AREA. ONCE AGAIN
THE LOWER TEMPERATURE PROFILE SUPPORTS A WINTRY MIX AT FIRST. AS
COLDER AIR IS DRAWN INTO THE SYSTEM DURING THE DAY MONDAY THE
PRECIPITATION WILL BECOME ALL SNOW...ALTHOUGH A WINTRY MIX IS
WILL STILL BE POSSIBLE SOUTH CENTRAL. SNOW AMOUNTS UP TO 5 INCHES
IS POSSIBLE FAR SOUTHWEST THROUGH WEST CENTRAL...WHERE CURRENTLY NO
SNOW COVER IS FOUND.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM CDT SUN APR 7 2013
THE MAIN FORECAST PROBLEMATIC TIME PERIOD IN THE EXTENDED PERIOD IS
TUESDAY THROUGH TUESDAY NIGHT...WHERE LIGHT SNOW ACCUMULATIONS MAY
OCCUR ACROSS FAR SOUTHWEST AND FAR SOUTH CENTRAL NORTH DAKOTA.
LEANED MORE TOWARD A GFS/ECMWF SOLUTION AS THE NAM WAS DEEMED AN
OUTLIER BRINGING SYSTEMS TOO FAR NORTH.
THE LONG TERM BEGINS MONDAY NIGHT WITH THE LARGE LONGWAVE TROUGH
OVER THE CENTRAL/SOUTHERN ROCKIES NEARLY CUTTING OFF FROM THE MAIN
BELT OF THE WESTERLIES...AND A SURFACE CANADIAN HIGH PRESSURE SYSTEM
MOVING SOUTHWARD ACROSS NORTH DAKOTA. LINGERING ENERGY FROM THE
LARGE SYSTEM TO THE SOUTH SHOULD AFFECT THE SOUTHERN TIER OF
COUNTIES MONDAY NIGHT IN THE FORM OF LIGHT SNOW. LOW TEMPERATURES
EXPECTED TO RANGE FROM 5 ABOVE IN THE NORTH TO THE TEENS SOUTH.
THE MODELS BRING THE LARGE LONGWAVE TROUGH EASTWARD INTO THE
CENTRAL/SOUTHERN PLAINS...WITH SOME ENERGY MOVING NORTHWARD FAR
ENOUGH TO BRING CHANCES OF SNOW ALONG THE SOUTHERN TIER ON TUESDAY.
COOL WITH HIGHS ONLY 25 TO 35.
BY TUESDAY NIGHT THE UPPER LEVEL TROUGH ELONGATES ENOUGH TO BRING A
SURGE OF ENERGY FROM THE TROUGH NORTHWARD INTO CENTRAL NORTH
DAKOTA...BUT BY THIS TIME THE ASSOCIATED SURFACE LOW IN THIS LARGE
SYSTEM IS WELL ESTABLISHED OVER MISSOURI AND THE MAIN PRECIPITATION
SHIELD AND BAROCLINIC ZONE IS TO THE SOUTH AND EAST OF OUR AREA.
LOWS TUESDAY NIGHT FROM 10 NORTHWEST TO 20 SOUTH CENTRAL.
THUS TUESDAY THROUGH TUESDAY NIGHT...A PERIOD OF CONTINUOUS LIGHT
SNOW CHANCES ACROSS THE SOUTHERN TIER OF COUNTIES MAY RESULT IN 1 TO
4 INCHES OF SNOWFALL POSSIBLE MAINLY FROM SLOPE/BOWMAN COUNTIES
EASTWARD TO LAMOURE/DICKEY COUNTIES...WITH UP TO AN INCH OF SNOW
POSSIBLE AS FAR NORTH AS INTERSTATE 94.
WEDNESDAY THROUGH NEXT WEEKEND...AS THE MONDAY/TUESDAY SYSTEM EXITS
TO THE EASTERN US...A BROAD UPPER LEVEL TROUGH DEVELOPS OVER WESTERN
NORTH AMERICA. THIS REGIME WILL KEEP TEMPERATURES BELOW AVERAGE FOR
THIS TIME OF YEAR...AND BRING SMALL CHANCES OF PRECIPITATION OFF AND
ON BUT AT THIS TIME DO NOT SEE ANY SIGNIFICANT PRECIPITATION IN THE
OFFING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 107 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 06 UTC TAF PERIOD. LATEST
SATELLITE IMAGERY HAS SHOWN LOWERING CEILINGS TO LIFR CONDITIONS
WITHIN STRATUS...WITH LIFR TO IFR CEILINGS EXPECTED TO CONTINUE
THROUGH DAYBREAK...AND THEN IMPROVE TO IFR TO MARGINAL MVFR.
LOW PRESSURE ACROSS MONTANA WILL DEVELOP AND SNOW WITH SLEET AND
FREEZING RAIN WILL BEGIN TO IMPACT KDIK AFTER 09Z...SPREADING EAST
MONDAY MORNING IMPACTING OTHER TERMINALS. VISIBILITIES IN SNOW AND
BLOWING SNOW WILL LIKELY FALL TO IFR AND BELOW FOR KDIK-KBIS.
SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON FOR ALL BUT
KJMS- KDIK AND POSSIBLY KBIS WHICH MAY REMAIN MVFR-IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ017>020-031>034-040>044.
&&
$$
UPDATE...LTH
SHORT TERM...WAA
LONG TERM...JV
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
437 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
437 AM UPDATE...NOTICED THAT BOTH THE 08.00Z ECMWF AND 08.00Z/06Z
NAM INDICATE A DRY SLOT COMING THROUGH ALOFT TO SCOUR OUT THE ICE IN
THE CLOUDS FOR WEDNESDAY NIGHT AND THURSDAY. IF THIS COMES TO
FRUITION...WE MAY BE DEALING MORE WITH RAIN / FREEZING RAIN VERSUS
SNOW...AND THUS BACK TO WONDERING ABOUT OBJECT TEMPERATURES.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 7 2013
A COUPLE NORTHEAST MOVING UPPER AIR DISTURBANCES WILL BRING SWATHS
OF -SHRA ACROSS THE REGION...ONE TRACKING ACROSS SOUTHERN MN INTO
NORTHERN WI WITH THE OTHER ACROSS IOWA INTO SOUTHEAST WI. THE BULK
OF THE ACCUMULATIONS WILL BE NORTH AND SOUTH OF THE TAF SITES AS A
RESULT. ENOUGH FORCING FOR SCT/OCNL -SHRA AT KRST/KLSE OVERNIGHT
INTO THE MID MORNING HOURS OF MONDAY. CLOUDS WILL THICKEN AND
LOWER...WITH A PERIOD OF MVFR LIKELY. SEE SOME POTENTIAL OF IFR AT
KRST...PER RAP13/NAM12 BUFKIT SOUNDINGS.
THE SHORTWAVES EXIT MONDAY AFTERNOON...AND WITH SOME MIXING IN THE
LOWER ATMOSPHERE...THERE IS A GOOD CHANCE THAT THE BKN MVFR CIGS MIX
OUT TO SCT. ANY BREAK INTO SCATTERED SKIES WON/T LAST LONG. LOW
CLOUDS WILL QUICKLY RETURN MONDAY NIGHT AS A WARM FRONT SETS UP WEST
TO EAST ACROSS IOWA. RAIN WILL ALSO RETURN LATE THAT
EVENING...WITH TUE LOOKING LIKE A WET DAY. MVFR/IFR CIGS WILL
OCCUR...WITH SOME REDUCTIONS IN VSBY.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
350 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 7 2013
A COUPLE NORTHEAST MOVING UPPER AIR DISTURBANCES WILL BRING SWATHS
OF -SHRA ACROSS THE REGION...ONE TRACKING ACROSS SOUTHERN MN INTO
NORTHERN WI WITH THE OTHER ACROSS IOWA INTO SOUTHEAST WI. THE BULK
OF THE ACCUMULATIONS WILL BE NORTH AND SOUTH OF THE TAF SITES AS A
RESULT. ENOUGH FORCING FOR SCT/OCNL -SHRA AT KRST/KLSE OVERNIGHT
INTO THE MID MORNING HOURS OF MONDAY. CLOUDS WILL THICKEN AND
LOWER...WITH A PERIOD OF MVFR LIKELY. SEE SOME POTENTIAL OF IFR AT
KRST...PER RAP13/NAM12 BUFKIT SOUNDINGS.
THE SHORTWAVES EXIT MONDAY AFTERNOON...AND WITH SOME MIXING IN THE
LOWER ATMOSPHERE...THERE IS A GOOD CHANCE THAT THE BKN MVFR CIGS MIX
OUT TO SCT. ANY BREAK INTO SCATTERED SKIES WON/T LAST LONG. LOW
CLOUDS WILL QUICKLY RETURN MONDAY NIGHT AS A WARM FRONT SETS UP WEST
TO EAST ACROSS IOWA. RAIN WILL ALSO RETURN LATE THAT
EVENING...WITH TUE LOOKING LIKE A WET DAY. MVFR/IFR CIGS WILL
OCCUR...WITH SOME REDUCTIONS IN VSBY.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
408 AM MDT MON APR 8 2013
.SHORT TERM...FOR TODAY AND TONIGHT...A COMPLEX WEATHER PATTERN IS
SETTING UP ACROSS THE REGION. PACIFIC STORM IS DIGGING SOUTHEAST
ACROSS NORTHERN CALIFORNIA AT THIS TIME. LATEST MODELS HAVE BEEN
SHOWING A SLIGHT SHIFT NORTH IN THE STORM TRACK. BY 12 TUESDAY
MORNING...THE UPPER LEVEL LOW WILL BE CENTER JUST WEST OF THE FOUR
CORNERS WITH THE SURFACE LOW NEAR THE OKLAHOMA PAN HANDLE.
STILL A GOOD AMOUNT OF UNCERTAINTY ON THE PLACEMENT OF THE DRY LINE
AND WHEN THE COLD FRONT WILL PUSH THROUGH THE AREA. STILL APPEARS
THE DRY LINE WILL BE ROUGHLY ALONG A LINE FROM FORT MORGAN TO LIMON.
HOWEVER...THE LATEST RAP HAS IT NEAR DENVER EARLY THIS EVENING
BEFORE THE COLD FRONT PUSHES THROUGH. BEST CHANCE FOR THUNDERSTORMS
WILL OCCUR EAST OF WHERE THE DRY LINE SETS UP. DUE TO STRONG
SHEAR...SUPERCELLS WILL BE POSSIBLE WITH LARGE HAIL. SINCE LOW LEVEL
SHEAR WILL BE STRONG...TORNADOES WILL ALSO BE POSSIBLE WITH ANY
STRONG STORM THAT DEVELOPS.
MODELS ARE COMING INTO BETTER AGREEMENT OVER THE LAST HOUR IN
SHOWING THE COLD FRONT ENTERING COLORADO LATE THIS AFTERNOON AND
PUSHING THROUGH THE DENVER AREA AROUND 00Z. NORTH TO NORTHEAST
UPSLOPE WINDS BEHIND THE FRONT COMBINED WITH A STRONG DIFFLUENT FLOW
ALOFT WILL GENERATE LIFT THROUGH OUT THE AIRMASS. PRECIPITATION WILL
START OFF AS RAIN AND CHANGE OVER TO SNOW AS COLD AIR MOVES INTO THE
AREA. FOR THE DENVER AREA...WOULD EXPECT THE CHANGE OVER TO SNOW
AROUND MID TO LATE EVENING.
THE AREA IS ON THE EDGE OF THE HEAVIER SNOW. IF THIS SYSTEM KEEPS
TRENDING NORTH...THE HEAVY SNOW MAY END UP JUST TO OUR NORTH. ALSO
WHEN THE RAIN CHANGES TO SNOW WILL PLAY A BIG ROLE ON HOW MUCH SNOW
ACCUMULATES. THEREFORE WILL CONTINUE WITH THE WINTER STORM WATCH AT
THIS TIME AND NOT UPGRADE TO ANY WARNINGS.
DID INCREASE TEMPERATURES INTO THE MID TO UPPER 60S FOR MOST OF
NORTHEAST COLORADO. AIRMASS WILL LIKELY BE WARM ENOUGH TO SUPPORT
LOWER 70S...BUT EXPECT THE MOSTLY CLOUDY SKIES TO TAKE OFF A FEW
DEGREES FROM REACHING OUR FULL POTENTIAL.
.LONG TERM...AS MENTIONED A FEW DAYS AGO IT NEVER FAILS THAT
SOMETHING WILL MANY TIMES MESS UP A DECENT STORM AND IT APPEARS
THIS TIME WILL BE NO DIFFERENT. ALTHOUGH THERE IS GOOD AGREEMENT
THAT A CLOSED UPPER LEVEL LOW WILL BE NR THE FOUR CORNERS BY
12Z...BY TUE EVENING THE MODELS PRETTY MUCH SPLIT THE SYSTEM WITH
THE MAIN PIECE OF ENERGY LIFTING NE INTO EITHER SERN WY OR WRN
NEBRASKA. THE ECMWF TRACKS THIS FEATURE WEST OF NERN CO WHILE THE
NAM AND GFS HAVE IT MOVING ACROSS NERN CO ON TUE. THERE IS STILL
DECENT UPSLOPE TUE MORNING WITH FAVORABLE QG ASCENT SO STILL CAN
NOT RULE OUT SOME HEAVIER SNOW THRU MID TO LATE MORNING IN AND NR
THE FOOTHILLS AND POSSIBLY OVER THE PALMER DIVIDE. MEANWHILE OVER
THE PLAINS OF NERN CO A POTENTIAL DRY SLOT MAY DEVELOP WHICH WOULD
LIMIT HEAVY SNOW POTENTIAL EAST OF A STERLING TO LIMON LINE THRU
THE AFTN HOURS. FOR NOW WILL LEAVE WATCHES AS IS AND LET THE DAY
SHIFT SEE IF THE MODELS CAN COME TO A CONSENSUS ON WHERE BEST
HEAVY SNOWFALL POTENTIAL MAY OCCUR. WINDS WILL BE GUSTY ON TUE SO
STILL EXPECT AREAS OF BLOWING SNOW. HIGHS WILL BE WELL BLO NORMAL
WITH READINGS NOT GETTING OUT OF THE 20S.
BY TUE NIGHT INTO WED THE UPPER LEVEL LOW IS FCST TO STALL OVER
WRN NEBRASKA. THE ECMWF AND GFS SHOW DRIER AIR SPREADING OVER NERN
CO ALTHOUGH THERE IS STILL SOME MOISTURE IN THE MTNS WHICH MAY
LEAD TO A CHC OF LIGHT OROGRAPHIC SNOWS. MEANWHILE GUSTY NLY
WINDS WILL STILL OCCUR OVER THE PLAINS OF NERN CO THRU THE AFTN.
HIGHS ON WED DUE TO LINGERING COLD TEMPS IN THE 850-700 MB LAYER
WILL ONLY BE IN THE 30S OVER NERN CO.
FOR THU THE UPPER LEVEL WILL MOVE EASTWARD WITH NWLY FLOW ALOFT
OVER NRN CO. A DISTURBANCE IN THIS FLOW WILL MOVE ACROSS NRN CO
LATE THU AFTN OR EVENING. CROSS- SECTIONS SHOW MOISTURE
INCREASING THE MTNS WITH DECENT LAPSE RATES SO MAY SEE A GOOD CHC
OF SNOW IN THE AFTN AND EVENING. OVER NERN CO ANOTHER WK FNT IS
FCST TO MOVE ACROSS THE AREA BY EVENING BRIEFLY ENHANCING UPSLOPE
FLOW. THIS IS THE DISTURBANCE MOVES ACROSS ALONG WITH A DECENT
UPPER LEVEL JET THIS COULD LEAD TO A CHC OF PCPN LATE THU AFTN
INTO THU EVENING. WILL KEEP HIGHS ON THU WILL IN THE MID TO UPPER 40S
ACROSS THE PLAINS.
BY FRI THE FLOW ALOFT WILL REMAIN NWLY WITH QUITE A BIT OF
MOISTURE EMBEDDED IN THE FLOW. THE ECMWF AND GFS SHOW ANOTHER
POTENTIAL DISTURBANCE TRACKING ACROSS THE AREA FRI AFTN INTO FRI
EVENING WITH ANOTHER WEAK SURGE MOVING ACROSS NERN CO. THUS SHOULD
SEE ANOTHER CHC OF SNOW IN THE MTNS WITH AT LEAST A SLIGHT CHC OF
PCPN AT LOWER ELEVATIONS. AS FOR HIGHS WILL HAVE READINGS IN THE
UPPER 40S TO LOWER 50S OVER NERN CO.
FOR THE WEEKEND RIGHT NOW THE FLOW ALOFT IS SUPPOSED TO BECOME
MORE ZONAL WHICH WOULD LEAD TO WARMER TEMPERATURES AND DRIER
CONDITIONS.
&&
.AVIATION...SOUTH TO SOUTHEAST WINDS WILL PREVAIL THROUGH THE DAY
UNTIL A COLD FRONT PUSHES THROUGH AROUND 23-00Z. WINDS WILL TURN
NORTHERLY BEHIND IT. WILL BE A CHANCE FOR THUNDERSTORMS AFTER
21Z...BUT THE BEST CHANCE WILL BE OVER FAR EASTERN COLORADO. RAIN
WILL DEVELOP AFTER 00Z TONIGHT AND CHANGE TO SNOW AROUND 04-05Z.
SNOW WILL BE HEAVY AT TIMES. VISIBILITY WILL BE REDUCED TO QUARTER
MILE OR LESS AT TIMES DUE TO SNOW AND BLOWING SNOW. THE HEAVIEST
SNOW IS EXPECTED TO FALL FROM 06-18Z TUESDAY. SNOWFALL TOTALS AT THE
DENVER AIRPORTS ARE EXPECTED TO RANGE FROM 6 TO 12 INCHES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ042-044>046-048>051.
WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
FOR COZ033>036.
WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
FOR COZ038>041-043.
&&
$$
SHORT TERM...MEIER
LONG TERM....RPK
AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1030 AM EDT MON APR 8 2013
.DISCUSSION...
HIGH PRESSURE ANCHORED E OF THE CAROLINA COAST EXTENDING WEST ACRS
THE NRN GULF COAST WILL GENERATE A STEADY E/SE BREEZE ACRS THE FL
PENINSULA. UPSTREAM LOW LVL MOISTURE VALUES ARE RUNNING 75-80PCT...
HIGH ENOUGH TO GENERATE RESPECTABLE CLOUD COVER AS WELL AS ISOLD
-SHRAS OVER THE GULF STREAM.
WHILE RADAR HAS BEEN DETECTING THE FOR THE PAST SVRL HRS...NONE OF
THEM HAVE SURVIVED FOR LONG ONCE THEY MOVE OUT OF THE GULF STREAM
INTO THE COOLER SHELF WATERS. MORNING SOUNDINGS ALL SHOW A SHARP
SUBSIDENCE INVERSION IN THE H85-H70 LYR CAPPING THE LCL AIRMASS BTWN
6-7KT WITH PWAT VALUES AOB 1.0". FURTHERMORE...THE USAF 915HZ
PROFILER AT THE CAPE INDICATING WINDS A BIT MORE SE TODAY THAN
SUNDAY...AND ONLY 10-15KTS AT THAT.
LITTLE TO NO CHANCE ANY SHRAS WILL MAKE IT ONSHORE...IMPACT OF ANY
THAT DO WOULD BE NEGLIGIBLE. FCST WILL REMAIN DRY. MORNING PACKAGE
LOOKS FINE AS IT...NO NEED TO UPDATE THIS MORNING.
&&
.AVIATION...
THRU 09/18Z...PREVAILING VFR ALL SITES. BTWN 09/08Z-09/13Z...LCL
MVFR CIGS IN BR.
&&
.MARINE...
NO HIGHLIGHTS. RIDGE AXIS WILL GENERATE A LIGHT TO GENTLE E/SE
BREEZE ACRS THE LCL ATLC. THESE WINDS WILL CONTINUE TO PUSH A 3-4FT
SWELL TOWARD THE E FL COAST...DOMINANT PDS 9-10 SEC. RAP ANALYSIS
SHOWS THE FETCH AROUND THE BASE OF THE RIDGE HAS A MORE MORE ERLY
DIRECTION TODAY THAN SUNDAY...ALSO A BIT WEAKER AT 10-15KTS. LATEST
BUOY OBS INDICATE SEAS ARE RUNNING ABOUT A FOOT LOWER THAN FCST...
REASONABLE GIVEN THE WEAKER WIND FIELD...SUSPECT THE NRN BAHAMAS
ALSO INTERCEPTING SOME OF THE SWELL ENERGY. WILL MAKE NECESSARY
ADJUSTMENTS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...PENDERGRAST
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
858 AM EDT Mon Apr 8 2013
.NEAR TERM [Rest of Today into this Evening]...
The large scale longwave pattern is highlighted by digging trough
over Wrn states with low at base over Ern NV and a broad ridge Ewd
across Srn stream. At surface, high pressure is centered in Wrn Atlc
off Carolina coast with ridging Wwd across local area, FL Peninsula
and into Gulf of Mex. Nearest low pressure center OK/TX panhandle
with front Swd down TX into Old Mex.
During the rest of today into this eve, as a strong impulse with
100+ NNW winds dives SEWD from Ern most Pacific into CA, Wrn
trough will continue to amplify SEWD across Great Basin towards 4
Corners. In response mid/upper ridge will also amplify N/NE with
rising heights over Gulf of Mex and SE region. At surface, OK/TX
low moves Ewd while high drops Swd in Wrn Atlc resulting in local
flow veering to SE/S around Wrn periphery of this high.
All this will yield somewhat tighter local gradients with a
modest increase in winds and warmer than normal temperatures.
1000-850mb thickness supports inland highs 80 West to 84 East.
These same conditions moving off cooler waters should maintain
beach temps in the the low 70s. Local obs show broken 6k clouds
across Ern counties this morning and area RAP sounding shows
moisture pooling up to H85 so expect CU clouds to again develop
this aftn. Will tweak aftn sky group to reflect this. No rain is
expected.Later tonight, this veering flow will provide sufficient
low level moisture for at least patchy fog.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 80 56 84 58 85 / 0 0 0 0 10
Panama City 77 63 83 63 81 / 0 0 0 0 10
Dothan 81 59 85 61 85 / 0 0 0 0 10
Albany 82 59 85 61 85 / 0 0 0 0 10
Valdosta 82 57 85 60 85 / 0 0 0 0 10
Cross City 82 56 84 61 85 / 0 0 0 0 10
Apalachicola 74 61 78 62 76 / 0 0 0 0 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
Near Term/MARINE/Aviation/Long Term...Block
Short Term/FIRE WEATHER...Camp
HYDROLOGY...DVD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1002 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 953 AM CDT MON APR 8 2013
MCV AND THE ASSOCIATED PRECIPITATION IS STARTING TO MOVE ACROSS
LAKE MICHIGAN AND THE DOWNWARD MOTION BEHIND THE MCV HAS ENDING
THE RAIN ACROSS THE AREA. A RESPECTABLE OUTFLOW BOUNDARY LIES JUST
SOUTH OF THE CWFA AND THERE IS A VORT MAX CROSSING THE MISSOURI RIVER.
THE QUESTION NOW IS WILL PRECIPITATION REGENERATE THIS AFTERNOON.
IF THE RAP FCST SOUNDING TRENDS ARE CORRECT...THE CONVECTIVE
TEMPERATURE WILL SLOWLY INCREASE THROUGH LATE MORNING AND
AFTERNOON AND SHOULD BE HIGHER THAN THE FCST MAX TEMPERATURES.
THUS THE OUTFLOW BOUNDARY SOUTH OF THE CWFA SHOULD REMAIN QUIET.
WITH CONVECTIVE TEMPERATURES HIGHER THAN THE FCST MAX...THE
INCOMING VORT MAX SHOULD ONLY RESULT IN SOME PASSING CLOUDS. ..08..
UPDATE ISSUED AT 659 AM CDT MON APR 8 2013
HAVE JUST SENT OUT A QUICK UPDATE TO FRESHEN UP THE FORECAST FOR
RECENT RADAR TRENDS...TEMPERATURES AND WINDS. BAND OF RAINFALL IS
STILL ON TRACK TO MOVE OUT OF THE FORECAST AREA BY MID TO LATE
MORNING...WITH NO ADDITIONAL THUNDER.
ALSO UPDATED AVIATION SECTION BELOW.
&&
.SYNOPSIS...
ISSUED AT 330 AM CDT MON APR 8 2013
A NICE MCS IS ONGOING OVER THE FORECAST AREA THIS MORNING...WITH
A 40-50KT LOW LEVEL JET IMPINGING ON THE SOUTHWEST FLANK OF THE
SYSTEM...IN AN AREA OF VERY GOOD MID LEVEL CONVERGENCE AND A WEAK
850MB FRONT...AND BETTER SURFACE FRONT. MOST OF THE THUNDERSTORMS
ARE MOVING ACROSS MISSOURI THIS MORNING...WITH A BROAD AREA OF
RAIN AND EMBEDDED THUNDER ROTATING NORTHEAST ACROSS THE FORECAST
AREA. THE MCV WITH THIS MCS IS WHAT IS DRIVING SOME OF THE
EAST-NORTHEAST MOVEMENT...AND EXPECT THAT NEARLY ALL OF THE
FORECAST AREA WILL RECEIVE RAINFALL BEFORE THE EVENT IS OVER. THE
BEST RAINFALL RATES HAVE RANGED UP TO 4 TENTHS OF AN INCH PER
HOUR...BUT MORE LOCATIONS ARE RECEIVING BETWEEN 1 AND 3
TENTHS/HOUR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT MON APR 8 2013
TODAY THE MAIN CONCERN IS FOR HOW QUICKLY THIS MCS WILL MOVE EAST
OUT OF THE FORECAST AREA THIS MORNING. THEN...HAVE CONCERNS FOR
POSSIBLE CONVECTION ALONG THE FRONT DURING THE DAYTIME. AN
THEN...OUR NEXT MCS IS EXPECTED TONIGHT AS THE NEXT SHORTWAVE
MOVES OUT ACROSS THE AREA AND INTERACTS WITH THE SURFACE WARM
FRONT DRAPED ACROSS THE AREA. IN ALL...THIS IS A RATHER DAMP
FORECAST.
TODAY HAVE USED MCS TECHNIQUES AND MODELS AS WELL AS NOWCASTING
TECHNIQUES INDICATE THIS MCS WILL MOVE OUT OF THE EASTERN PORTIONS
OF THE FORECAST AREA ABOUT 15Z. UNTIL THEN THOUGH...AM CARRYING
SOME VERY HIGH POPS FOR ABOUT THE SOUTHERN THREE QUARTERS OF THE
AREA. DO NOT EXPECT MUCH ADDITIONAL THUNDER DEVELOPMENT AS WE ARE
GETTING INTO THE TIME RANGE WHEN THE LOW LEVEL JET SHOULD START TO
WEAKEN. THERE MAY BE SOME LINGERING SHOWERS PAST 15Z...BUT HAVE
KEPT POPS PRETTY LOW FOR NOW.
THEN...WE SHOULD MANAGE TO BREAK OUT INTO AT LEAST A LITTLE
SUNSHINE AS THE CLOUDS WITH THE MCS ARE SWEPT EAST. THIS SHOULD
ALLOW TEMPERATURES TO RISE INTO THE 60S AND EVEN LOW TO MID
70S...MAINLY SOUTHWEST WHERE THE SUNSHINE BREAKS OUT SOONEST. THE
WARM FRONT WILL BE DRAPED FROM EAST TO WEST ACROSS THE FORECAST
AREA OVER ABOUT THE NORTHERN THIRD OF THE AREA BY AFTERNOON...AND
THE WARM AIR THAT SURGES INTO THE AREA ON THE SOUTH SIDE OF THE
BOUNDARY SHOULD HELP BOOST TEMPS AS WELL. THE MCS WILL HAVE LEFT
BEHIND AN OUTFLOW BOUNDARY WHICH MAY SERVE AS A FOCUS FOR
ADDITIONAL THUNDERSTORM DEVELOPMENT THIS AFTERNOON...AND AM
CARRYING SOME LOW CHANCE POPS FOR THEN.
TONIGHT THE NEXT SURGE OF WAA AND THETA-E ADVECTION SHOULD CAUSE
THUNDERSTORMS TO BEGIN DEVELOPING OVER THE AREA DURING THE
EVENING...AND GRADUALLY INCREASING IN COVERAGE OVERNIGHT. AS THERE
ARE NOT ANY INITIAL STRONG FEATURES TO PIN DOWN AND TIMING IS
SOMEWHAT PROBLEMATIC...HAVE PLACED HIGHEST POPS ALONG THE WARM
FRONT AND GONE SLIGHTLY LOWER TOWARDS THE SOUTH. THIS WILL NEED
SOME REFINEMENT AS FEATURES SET UP LATER TODAY. MIN TEMPS SHOULD
BE KEPT MILD BY THE WARM AIRMASS AND AT LEAST BROKEN CLOUD COVER.
MIN TEMPS ONLY EXPECTED TO FALL INTO THE 50S.
LE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 330 AM CDT MON APR 8 2013
FORECAST FOCUS ON MAJOR SLOW MOVING STORM SYSTEM THIS WEEK THEN
COLDER TEMPERATURES BEHIND THE SYSTEM. FORECAST BASED ON THE MORE
CONSISTENT ECMWF MODEL...THE GFS SEEMS A BIT TOO AGGRESSIVE WITH
MOVING THE DEEP TROUGH TO THE EAST TOO QUICKLY.
TUESDAY THROUGH WEDNESDAY...SEVERAL ROUNDS OF WIDESPREAD SHOWERS AND
THUNDERSTORMS AS DEEP WESTERN TROUGH PUSHES SLOWLY ACROSS THE
MIDWEST. FRONTAL BOUNDARY WILL BE LOCATED IN THE CWA ALONG WITH
CONTINUED EXCELLENT FEED OFF THE GULF. PRECIPITABLE WATER WILL BE
WELL OVER AN INCH WITH THE POTENTIAL FOR HEAVY RAIN AMOUNTS OF AT
LEAST 1 TO 3 INCHES DURING THIS TIME FRAME ESPECIALLY IF REPEATED
BOUTS OF THUNDERSTORMS TRAIN OVER THE SAME AREAS. WARM ON TUESDAY
WITH HIGHS IN THE 70S ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80.
WEDNESDAY IS THE DAY WHEN THE MAIN TROUGH/DYNAMICS ARRIVE WITH THE
HEAVIEST RAINS AND POSSIBLE SEVERE WEATHER. HOWEVER THIS WILL DEPEND
ON EXACT TRACK OF THE SURFACE LOW...TIMING OF THE STRONG COLD FRONT
AND AMOUNT OF INSTABILITY. AT THIS POINT SPC HAS A SLIGHT RISK FOR
SEVERE IN OUR SOUTHERN COUNTIES TUESDAY AND TUESDAY NIGHT WITH THE
MAIN THREAT OF SEVERE ON WEDNESDAY MAINLY EAST/SOUTH OF THE DVN
CWA.
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...COLDER AIR WILL BE FILTERING
INTO THE REGION AS THE DEEP TROUGH PUSHES EASTWARD. LOOKS COLD
ENOUGH FOR EITHER A RAIN/SNOW MIX OR ALL SNOW BUT MUCH OF THE
AVAILABLE MOISTURE WILL HAVE PUSHED EAST OF THE CWA BY THE TIME THE
COLD AIR ARRIVES. THEREFORE NOT EXPECTING ANY ACCUMULATION. LOOKS
DRY ON FRIDAY. HOWEVER...TEMPERATURES WILL BE BELOW NORMAL WITH
HIGHS MAINLY IN THE 40S WITH LOWS DIPPING INTO THE 20S AT SOME
LOCATIONS.
THIS WEEKEND/WEEK 2...THE 00Z ECMWF HAS BACKED OFF ON RAIN ARRIVING
LATER THIS WEEKEND AND NOW INDICATES DRY WEATHER ALONG WITH WARMING
TEMPERATURES. THIS AHEAD OF ANOTHER MAJOR TROUGH DIGGING INTO THE
WESTERN STATES. THIS FITS THE TELECONNECTIONS WITH THE AO/NAO GOING
NEUTRAL TO POSITIVE AND THE PNA GOING NEGATIVE. THIS FAVORS AN
ACTIVE STORM TRACK IN THE MIDDLE OF THE COUNTRY WITH DEEP TROUGHING
IN THE WEST AND RIDGING IN THE EAST. IF THE ECMWF IS CORRECT THEN IT
WILL BE DRY UNTIL NEXT TUESDAY WHEN A VIGOROUS NEGATIVE TILT TROUGH
AND DEEPENING SURFACE LOW ARRIVES FOLLOWED BY COOLER TEMPERATURES
AGAIN.
HAASE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 659 AM CDT MON APR 8 2013
BAND OF RAINFALL CURRENTLY AFFECTING KCID AND KMLI WITH MVFR CIGS
AND LIFR CIGS AT KDBQ WILL GRADUALLY IMPROVE THIS MORNING AS THE
BAND OF RAIN MOVES EAST. SOME FOG POSSIBLE AT KCID NEXT FEW HOURS. KCID
TO IMPROVE TO VFR FIRST...FOLLOWED BY KDBQ AND KMLI BY NO LATER
THAN 16Z. CONDITIONS SHOULD REMAIN VFR THROUGH THE REST OF TODAY
AND INTO AT LEAST THE EARLY PART OF TONIGHT. SHOWERS AND
THUNDERSTORMS TO REDEVELOP AFTER 03Z TONIGHT...BRINGING AT LEAST
IFR CONDITIONS FOR BOTH CIGS AND VSBYS...BECOMING MORE WIDESPREAD
AFTER 06Z AND POSSIBLY LOWERING TO LIFR. HAVE LEFT LIFR CONDITIONS
OUT OF FORECAST FOR NOW DUE TO TIMING UNCERTAINTIES. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...HAASE
AVIATION...LE
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
1028 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1028 AM CDT MON APR 8 2013
12Z UPPER AIR ANALYSIS INDICATED THE EML HAS YET TO ADVECT INTO
NORTHEAST KS WITH THE WARMER 700 MB TEMPS STILL ACROSS OK. THE RAP
AND NAM INDICATE THE WARM AIR ADVECTION PATTERN AND WEAK
ISENTROPIC LIFT WILL PERSIST THROUGH THE DAY. WITH THE CAP NOT AS
STRONG AS EARLIER ANTICIPATED...HAVE PUT A SLIGHT CHANCE FOR
SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST FOR THIS
AFTERNOON ACROSS NORTH CENTRAL AND NORTHEAST KS THINKING THERE
COULD BE SOME POPCORN CONVECTION ON THE NORTHERN EDGE OF THE EML.
THE RAP AND HRRR ARE SHOWING THIS POTENTIAL AND AGITATED CU FIELD
ACROSS CENTRAL KS SHOWS THERE IS SOME ELEVATED INSTABILITY TO WORK
WITH.
UPDATE ISSUED AT 642 AM CDT MON APR 8 2013
WEAK ISENTROPIC LIFT MAY CAUSE A FEW ISOLATED SHOWERS ALONG THE
WESTERN AND SOUTHERN COUNTIES OF THE CWA THIS MORNING. ONCE THE
BOUNDARY LAYER MIXES ABOVE 925MB THESE WEAK RAIN SHOWERS SHOULD
DISSIPATE AROUND 10 AM. PATCHY GROUND FOG WAS DEVELOPING AROUND
THE CWA...SO I HAVE INCLUDED PATCHY FOG IN THE FORECAST THROUGH 10
AM.
UPDATED THE AVIATION DISCUSSION AS WELL.
GARGAN
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT MON APR 8 2013
TODAY...AN INTENSE UPPER LEVEL TROUGH WILL DIG SOUTHEAST FROM OR AND
NORTHERN CA INTO NV AND NORTHERN AZ BY LATE THIS AFTERNOON. A LEE
SURFACE LOW WILL DEEPEN OVER SOUTHEAST CO...CAUSING SURFACE AND
850MB WINDS TO BACK TO THE SOUTHEAST ACROSS MUCH OF KS. THE STRONGER
WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL KS DURING THE
AFTERNOON HOURS WITH WINDS INCREASING TO NEAR 30 MPH WITH GUSTS TO
40 MPH. WINDS ACROSS THE CWA WILL INCREASE TO 15 TO 25 MPH WITH
GUSTS OF 30 MPH ACROSS NORTH CENTRAL KS DURING THE AFTERNOON HOURS.
A SURFACE DRYLINE WILL PUNCH NORTHEAST INTO EXTREME SOUTHWEST KS
DURING THE AFTERNOON HOURS AND THEN ARC NORTHWEST INTO NORTHEAST CO.
SURFACE CONVERGENCE AHEAD OF THE DRYLINE...ALONG WITH ASCENT AHEAD
OF THE H5 TROUGH MOVING INTO NORTHERN AZ...WILL CAUSE THUNDERSTORMS
TO DEVELOP DURING THE AFTERNOON HOURS ACROSS WESTERN KS AND
NORTHEAST CO. VERTICAL WIND SHEAR PROFILES AND SUFFICIENT
INSTABILITY WILL ALLOW FOR SOME SEVERE THUNDERSTORMS TO DEVELOP
ACROSS WESTERN KS AND NORTHEAST CO. THOUGH...IF THE CLOUD COVER
HOLDS THROUGH THE DAY ACROSS WESTERN KS THEN THE INSTABILITY MAY NOT
BE SUFFICIENT FOR SEVERE THUNDERSTORMS. A COMPLEX OF STRONG TO
SEVERE STORMS MAY MOVE INTO NORTH CENTRAL KS TONIGHT.
ACROSS EASTERN KS...A COMBINATION OF BOTH THE DOWN STREAM H5 RIDGE
AMPLIFYING AND AN EML SPREADING NORTHEAST ACROSS THE CWA WILL CREATE
A STRONG CAPPING INVERSION. THE CAPPING INVERSION SHOULD PREVENT ANY
SURFACE BASED THUNDERSTORMS FROM DEVELOPING. THERE MAY
BE SOME ISOLATED SHOWERS SOUTH OF I-70 DURING THE DAY DUE TO THE
INCREASING DEEP MOISTURE ADVECTION...BUT AT THIS TIME THE MOIST
PARCELS SHOULD NOT BE FORCED TO THEIR LEVEL OF FREE CONVECTION
ABOVE THE CAPPING INVERSION. THEREFORE...I ONLY WENT WITH 14 POPS
DURING THE DAY.
THE STRATUS CLOUD COVER MAY HOLD IN FOR MOST OF THE DAY BUT IF THERE
ARE SOME BREAKS IN THE CLOUD COVER THIS AFTERNOON HIGH TEMPERATURES
MAY REACH THE MID 70S...BUT IN AREAS WHERE THE CLOUD COVER HOLDS
HIGHS MAY ONLY REACH AROUND 70 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 344 AM CDT MON APR 8 2013
TONIGHT...THE BEST CHANCES FOR THUNDERSTORMS TONIGHT WILL BE ACROSS
THE NORTHERN CWA FROM LATER THIS EVENING THROUGH THE OVERNIGHT HOURS
AS CONVECTION THAT DEVELOPS IN THE HIGH PLAINS/NORTHWEST KS
SPREADS/DEVELOPS EASTWARD...ALTHOUGH THE OVERALL AREA OF CONVECTION
APPEARS WILL BE EVEN FURTHER NORTH AND WEST THAN PREVIOUS TRENDS
WITH FORECAST INHIBITION EVEN MORE PRONOUNCED SOUTH AND EAST. HAVE
THEREFORE LOWERED POPS ACROSS THE EAST CENTRAL NOT ONLY FOR TONIGHT
BUT ALSO FOR TUESDAY MORNING AS HIGHER QPF REMAINS WELL NORTH AND
WEST CLOSER TO THE FRONT.
AS THE PRIMARY SHORTWAVE TROUGH ROTATES OUT OF THE ROCKIES AND INTO
THE NORTHERN HIGH PLAINS...THE COLD FRONT WILL SURGE EASTWARD
THROUGH THE DAY...MOVING THROUGH MUCH OF THE NORTH CENTRAL COUNTIES
IN THE MORNING AND TO NEAR THE TURNPIKE BY LATE AFTERNOON BEFORE
CLEARING THE REMAINDER OF THE EASTERN COUNTIES THROUGH THE EVENING.
MUCH OF THE EARLY DAY CONVECTION WILL LIKELY OCCUR ALONG AND JUST
BEHIND THE FRONT BEFORE SHIFTING SOUTH AND EAST WITH THE FRONT INTO
THE EVENING HOURS OVER THE EAST CENTRAL COUNTIES AS LARGE SCALE
ASCENT SPREADS NORTH AND EASTWARD ALONG AND JUST BEHIND THE FRONT
LATER IN THE AFTERNOON AND EVENING. ALTHOUGH SHEAR WILL REMAIN
STRONG AHEAD OF FRONT...THE STRONG CAPPING INVERSION WILL ALSO
REMAIN IN PLACE. WHEN COMBINED WITH THE FASTER FROPA...CLOUD COVER
AND EXTENSIVE PRECIP...THE OVERALL INSTABILITY AND SEVERE WEATHER
POTENTIAL IS HARDER TO PINPOINT. ALTHOUGH STRONG CONVECTION WILL BE
POSSIBLE ALONG THE FRONT THROUGH THE DAY...THE MOST ACTIVE PERIOD
APPEARS WILL SETUP ACROSS NORTHEAST AND EAST CENTRAL KS IN THE
MID/LATE AFTERNOON AS THE FRONT PUSHES THROUGH AS THE MAIN SHORTWAVE
TROUGH LIFTS OUT INTO THE PLAINS. SCATTERED STRONG TO SEVERE
THUNDERSTORMS MAY FORM A SQUALL LINE INTO THE EVENING AS IT PUSHES
EASTWARD. THIS SHOULD ALSO BE THE TIME OF THE HEAVIER PRECIP ACROSS
THE SOUTHEAST COUNTIES. AS COLDER AIR WORKS SOUTH AND EAST INTO THE
CWA LATE TUESDAY NIGHT AND INTO WED...A RAIN/SNOW MIX IS POSSIBLE
ACROSS THE WESTERN 1/3 OF THE CWA...THEN POSSIBLY OVER THE REMAINDER
OF THE NORTH/NORTHEAST CORNER WEDNESDAY NIGHT/EARLY THU MORNING. AT
THIS TIME...ONLY LIGHT SNOWFALL AMOUNTS...IF ANY...ARE EXPECTED
ACROSS THE FAR NORTHWEST COUNTIES. HOWEVER...IF THE SYSTEM OR DRY
SLOT MOVES OUT FURTHER SOUTH AND EAST THAN FORECAST...MORE IN THE
WAY OF ACCUMULATING SNOW WOULD BE POSSIBLE IN THE NORTH CENTRAL AND
BORDER COUNTIES ALONG THE NORTHERN BORDER.
EITHER WAY...IT SHOULD BE DRY ACROSS THE CWA BY THU AFTERNOON INTO
FRIDAY BEFORE ANOTHER CHANCE FOR SHOWERS RETURNS TO THE AREA OVER
THE WEEKEND AS WARM AIR ADVECTION INCREASES AHEAD OF ANOTHER
SHORTWAVE TROUGH. HIGHS IN THE 40S ON THURSDAY SHOULD WARM BACK INTO
THE 60S AND 70S FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 642 AM CDT MON APR 8 2013
IN AREAS WHERE THE STRATUS HAS CLEARED...PATCHY GROUND FOG HAS
FORMED. VISIBILITIES WERE AS LOW AS ONE HALF AT KTOP. THE GROUND
FOG SHOULD DISSIPATE AROUND 15Z. THE MVFR STRATUS SHOULD REFORM
WITH CEILINGS OF 1800 TO 2500 FT...AS DEEPER MOISTURE ADVECTS
NORTHWARD. I CANNOT RULE OUT AN ISOLATED SHOWER THROUGH THE
MORNING HOURS. MHK MAY SEE AN INCREASING CHANCE FOR THUNDERSTORMS
DURING THE EARLY MORNING HOURS OF TUESDAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WOLTERS
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
647 AM CDT MON APR 8 2013
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 601 AM CDT MON APR 8 2013
WARM FRONT HAS MOVED N OF THE TAF SITES LEADING TO S-SWLY SFC
WINDS TODAY AND S-SELY SFC WINDS TGT. ALTHOUGH THERE SHOULD BE SCT-
BKN VFR...LOW LEVEL CLOUDS TODAY AND TGT IT APPEARS THAT THE
MODELS ARE OVERDOING THE LOW LEVEL...BOUNDARY LAYER RH AND ARE
TOO LOW WITH THE CLOUD CEILING FORECAST IN THE MOS GUIDANCE. FOR
NOW WILLL KEEP IT VFR THROUGH THE PERIOD IN THE TAF FORECASTS.
THERE IS ALSO THE POTENTIAL FOR WIDELY SCATTERED SHOWERS OR STORMS
THIS AFTN ACROSS MUCH OF THE AREA...AND SCATTERED SHOWERS AND
STORMS ACROSS NERN MO AND W CNTRL IL TGT. WITH PLENTY OF UNCERTAINTY
WITH TIMING AND LOCATION OF THE CONVECTION WILL LEAVE THE TAFS DRY
FOR NOW.
SPECIFICS FOR KSTL...WITH PLENTY OF LOW LEVEL MOISTURE AND
INSTABILITY THERE WILL BE SCT-BKN DIURNAL CUMULUS CLOUDS THIS
AFTN. MOST OF THIS SHOULD BE VFR. WILL LIKELY HAVE AT LEAST SCT
LOW LEVEL CLOUDS TGT INTO TUE MRNG. THERE MAY BE WIDELY SCATTERED
TO SCATTERED SHOWERS AND STORMS THIS AFTN AND TGT...BUT WILL
LEAVE THE STL TAF DRY FOR NOW WITH NO WELL DEFINED SFC BOUNDARY OR
FORCING MECHANISM TO FOCUS AND INITIATE CONVECTION. S-SWLY SFC
WIND SHOULD CONTINUE TODAY...THEN BECOME MORE S-SELY THIS EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
934 AM MDT MON APR 8 2013
.SHORT TERM...VALID FOR TDY AND TUE...
FRONTOGENETICALLY-INDUCED SNOW CONTINUES ITS TREK ACROSS SOUTHEAST
MT THIS MORNING...WITH VISIBILITY DOWN TO 1/4SM AT BAKER AT TIMES.
REPORTS IN THE WAKE OF THIS BAND OVERNIGHT WERE GENERALLY IN THE 3
TO 5 INCH RANGE FROM NEAR HARLOWTON TO ROUNDUP...FORSYTH AND MILES
CITY. THE 12 UTC NAM AND RECENT RAP RUNS SHOW THE FRONTOGENESIS IN
THE 850-700 HPA LAYER OVER SOUTHEASTERN MT WILL WEAKEN BY ABOUT 18
UTC AS THE BETTER FORCING SHIFTS INTO NORTH DAKOTA. THIS IDEA FITS
UPSTREAM TRENDS WELL WITH IMPROVING VISIBILITIES AT MILES CITY. IT
LOOKS LIKE WE WILL BE ABLE TO LET THE HARLOWTON AND JUDITH GAP TO
ROUNDUP PART OF THE WINTER WEATHER ADVISORY EXPIRE AS SCHEDULED AT
18 UTC. THE MILES CITY TO BAKER PART OF IT MIGHT BE DROPPED DURING
THE MID AFTERNOON...BUT GIVEN WEAK UPSLOPE SOME LIGHT SNOW WILL BE
GOING ON EVEN BEHIND THE MAIN BAND...SO WE PLAN TO BE SLOW TO DROP
THE HEADLINES GIVEN CONTINUED SLIPPERY ROADS.
ONLY MINOR CHANGES WERE MADE TO THE FORECAST WITH THIS UPDATE. THE
POPS AROUND SHERIDAN WERE REDUCED THIS MORNING BECAUSE THE FORCING
TIED TO THE EVOLVING 500-HPA TROUGH IN THE CENTRAL ROCKIES DOESN/T
LOOK TO REACH THERE UNTIL CLOSER TO 21 UTC. OTHERWISE...ONLY A FEW
OBSERVATIONALLY-BASED ADJUSTMENTS WERE MADE TO TODAY/S FORECAST AT
THIS POINT...INCLUDING LOWERING HIGHS A FEW DEGREES IN MOST SPOTS.
OUR MAIN FOCUS HEADING FORWARD WILL BE ON DETERMINING THE NORTHERN
EXTENT OF HEAVY SNOW TONIGHT AND TUESDAY...WITH POTENTIAL FOR 6 OR
MORE INCHES FROM SHERIDAN TO MOORHEAD AND ALBION. THE QPF FROM THE
12 UTC NAM STRONGLY SUPPORTS UPGRADING OUR WINTER STORM WATCH TO A
WARNING. HOWEVER...WE WILL TAKE A LOOK AT THE REMAINDER OF THE NEW
MORNING GUIDANCE BEFORE MAKING A DECISION ON HEADLINES TONIGHT AND
TUESDAY BY THE EARLY TO MID AFTERNOON. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
DRY WEDNESDAY WITH MODERATION IN TEMPERATURES WILL BE FOLLOWED BY
A PACIFIC FRONT OVERNIGHT WHICH WILL BRING A PREVALENT NORTHWEST
FLOW ON THURSDAY AND FRIDAY. BY SATURDAY THE FLOW BEGINS TO BACK
AS AN UPPER LOW OVER THE GULF OF ALASKA TRACKS SOUTHWARD ALONG THE
BC COAST. THIS PUSHES ANOTHER COLD FRONT THROUGH THE REGION
DURING THE WEEKEND. JET STREAM REMAINS SOUTH OF THE REGION FOR
EARLY NEXT WEEK WITH TEMPERATURES BELOW NORMAL.
BEST CHANCES FOR PRECIPITATON WILL BE WITH THE WEDNESDAY NIGHT
FRONT AND THEN AS THE FLOW BACKS DURING THE WEEKEND IN RESPONSE TO
THE BC LOW. NO PARTICULAR PERIOD LOOKS IMPRESSIVE AT THIS POINT
FOR SIGNIFICANT WIDESPREAD BUT UNSETTLED WEATHER SHOULD BE
EXPECTED AFTER WEDNESDAY. TEMPERATURES WILL REMAIN NEAR NORMAL
THURSDAY THROUGH SATURDAY BEFORE FALLING SUNDAY. BORSUM
&&
.AVIATION...
LATE SEASON WINTER STORM CONTINUES TO MOVE ACROSS CENTRAL AND
EASTERN MONTANA THIS MORNING. WIDESPREAD IFR CONDITIONS WILL
PERSIST THROUGH THE MORNING HOURS ESPECIALLY NEAR KMLS AND
KBHK...DUE TO SNOW AND FOGGY CONDITIONS. NORTHERLY WINDS MAY PICK
UP BY THIS AFTERNOON NEAR KMLS AND KBHK MAKING CONDITIONS WORSE AT
TIMES. SNOWFALL MAY INCREASE AT ALL TERMINALS AGAIN THIS AFTERNOON
AS WELL. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 028 015/036 019/045 030/056 034/053 032/053 030/052
+/S 31/B 01/B 33/W 22/W 33/W 33/W
LVM 030 015/037 021/049 030/053 030/051 029/050 027/049
8/S 41/B 01/B 32/W 22/W 33/W 33/W
HDN 030 017/035 015/045 026/057 029/054 027/054 027/054
9/S 41/B 11/B 33/W 22/W 33/W 33/W
MLS 029 016/032 016/041 023/052 028/052 028/052 026/052
+/S 21/B 11/B 23/W 22/W 33/W 32/W
4BQ 032 010/031 011/039 019/052 025/051 026/051 025/051
7/O 87/S 31/B 23/W 23/W 23/W 33/W
BHK 029 010/028 013/036 017/045 028/046 026/046 022/046
+/S 42/S 11/B 23/W 22/W 23/W 32/W
SHR 031 016/031 015/040 021/054 028/051 027/052 025/051
8/O 87/S 21/B 23/W 23/W 23/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MDT TODAY FOR
ZONES 28-29-42-63.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MDT THIS EVENING
FOR ZONES 31>33.
WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONES 36-37.
WY...WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
955 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 944 AM CDT MON APR 8 2013
UPGRADING TO WINTER STORM WARNING FOR HEAVY SNOW SOUTHWEST
COUNTIES OF GOLDEN VALLEY...BILLINGS...STARK...DUNN...HETTINGER
MCKENZIE...SLOPE. RADAR ANS SURFACE REPORTS SHOW BAND OF HEAVY
SNOW WILL EXTEND ACROSS THE SOUTHWEST. MOST OF THE HEAVY SNOW WILL
FALL THROUGH EARLY AFTERNOON THEN BEGIN TO DIMINISH.
UPDATE ISSUED AT 650 AM CDT MON APR 8 2013
SURFACE OBSERVATIONS AT STANLEY...MINOT AIR FORCE BASE AND BELCOURT
ARE INDICATING FREEZING RAIN. ALSO A REPORT OF FREEZING RAIN AND
SLEET AT LANSFORD. FORECAST SOUNDINGS INDICATE THIS SHOULD BE A
SHORT LIVED EVENT...WITH COLUMN CONTINUING TO COOL. THERE WAS ALSO
RAIN LAST NIGHT THAT HAS NOW FROZEN TO SURFACES. WILL ISSUE A
FREEZING RAIN ADVISORY TO COVER THE ICY CONDITIONS THROUGH THE
MORNING COMMUTE. WILL GO THROUGH NOON AND LET THE DAY SHIFT CANCEL
IF NEEDED.
SNOW CONTINUES TO LIFT NORTH AND EAST THROUGH SOUTHWEST NORTH
DAKOTA. NO CHANGES TO THE SNOW AND BLOWING SNOW ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 944 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 12 UTC TAF PERIOD.
WIDESPREAD LOW IFR TO IFR CONDITIONS ACROSS WEST AND CENTRAL NORTH
DAKOTA. HEAVY SNOW AND BLOWING SNOW KDIK. LIGHT SNOW KISN-KMOT-
KDIK-KJMS.
SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON/EVENING FOR ALL
BUT KJMS-KDIK AND POSSIBLY KBIS WHICH MAY REMAIN IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ009-019-020-034-042>044.
WINTER STORM WARNING UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY FOR
NDZ017-018-031>033-040-041.
FREEZING RAIN ADVISORY UNTIL NOON CDT TODAY FOR NDZ003>005-
010>013.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
650 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 650 AM CDT MON APR 8 2013
SURFACE OBSERVATIONS AT STANLEY...MINOT AIR FORCE BASE AND BELCOURT
ARE INDICATING FREEZING RAIN. ALSO A REPORT OF FREEZING RAIN AND
SLEET AT LANSFORD. FORECAST SOUNDINGS INDICATE THIS SHOULD BE A
SHORT LIVED EVENT...WITH COLUMN CONTINUING TO COOL. THERE WAS ALSO
RAIN LAST NIGHT THAT HAS NOW FROZEN TO SURFACES. WILL ISSUE A
FREEZING RAIN ADVISORY TO COVER THE ICY CONDITIONS THROUGH THE
MORNING COMMUTE. WILL GO THROUGH NOON AND LET THE DAY SHIFT CANCEL
IF NEEDED.
SNOW CONTINUES TO LIFT NORTH AND EAST THROUGH SOUTHWEST NORTH
DAKOTA. NO CHANGES TO THE SNOW AND BLOWING SNOW ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 126Z MONDAY NIGHT)
ISSUED AT 650 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 06 UTC TAF PERIOD. LATEST
SATELLITE IMAGERY HAS SHOWN LIFR TO IFR CONDITIONS IN STRATUS AND
FOG. LIFR TO IFR CEILINGS ARE EXPECTED TO CONTINUE THROUGH
DAYBREAK...AND THEN IMPROVE TO IFR TO MARGINAL MVFR.
LOW PRESSURE ACROSS MONTANA WILL DEVELOP AND SNOW WITH SLEET AND
FREEZING RAIN WILL BEGIN TO IMPACT KDIK AFTER 12Z...SPREADING
EAST MONDAY MORNING IMPACTING OTHER TERMINALS. VISIBILITIES IN
SNOW AND BLOWING SNOW WILL LIKELY FALL TO IFR AND BELOW FOR KDIK-
KBIS. SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON FOR ALL BUT
KJMS- KDIK AND POSSIBLY KBIS WHICH MAY REMAIN MVFR-IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ017>020-031>034-040>044.
FREEZING RAIN ADVISORY UNTIL NOON CDT TODAY FOR NDZ003>005-
010>013.
&&
$$
UPDATE...TWH
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...LTH
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1044 AM CDT MON APR 8 2013
.UPDATE...
INCREASED HIGH TEMPERATURES A FEW DEGREES ACROSS SOUTHWEST
OKLAHOMA AND FAR WESTERN NORTH TEXAS THIS AFTERNOON. TWEAKED LATE
AFTERNOON/EVENING STORM CHANCES AS WELL AS SKY COVER AND WINDS.
&&
.DISCUSSION...
THE CHALLENGE OF THE DAY IS DETERMINING WHETHER OR NOT A FEW
STORMS WILL DEVELOP ACROSS WESTERN OKLAHOMA AND WESTERN NORTH
TEXAS LATE THIS AFTERNOON AND EVENING.
BASED ON SURROUNDING RAOBS THIS MORNING...A RATHER STRONG CAP
IS IN PLACE ACROSS THE REGION. TO BREAK IT...CONVECTIVE TEMPERATURES
MUST REACH THE 86 TO 93 DEGREE RANGE...WHICH SEEMS TO ONLY BE
POSSIBLE ACROSS FAR SOUTHWEST OKLAHOMA AND FAR WESTERN NORTH TEXAS
ACCORDING TO LATEST MODELS. SINCE THESE AREAS ARE SUNNY AT THIS
MOMENT AND BASED ON LATEST HRRR RUNS...INCREASED HIGHS IN THESE
AREAS WITH HIGHS IN THE LOWER TO PERHAPS MID 90S WEST OF A SAYRE
TO ALTUS TO SEYMOUR LINE.
FOR NOW...KEPT A 20 PERCENT CHANCE FOR STORMS MAINLY NEAR A
WOODWARD TO KNOX CITY LINE BETWEEN 4 AND 7 PM CDT...AND NEAR
AN ALVA TO WEATHERFORD TO VERNON LINE 7 PM CDT TO 1 AM CDT. IF
STORMS DEVELOP...WHICH REMAINS A BIG...THEY WOULD BE HIGH BASED
AT FIRST WITH DAMAGING WIND AS THE MAIN HAZARD...BUT COULD
INTENSIFY QUICKLY AS THEY MOVE EAST INTO DEEPER MOISTURE AND
BETTER INSTABILITY...SUGGESTING A LARGE HAIL AND PERHAPS A
TORNADO THREAT. CONFIDENCE OF ANY STORMS DEVELOPING THIS
AFTERNOON AND EVENING REMAINS LOW AS NOT SURE IF THE CAP CAN
BE OVERCOME...ESPECIALLY WITHOUT A MID/UPPER LEVEL TRIGGER TO
PROVIDE LIFT.
FOR THE OKLAHOMA CITY METRO AREA...THUNDERSTORMS ARE NOT
EXPECTED THROUGH MIDDAY TUESDAY.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.FIRE WEATHER...
WILL BE CLOSE TO CRITICAL FIRE WEATHER CONDITIONS BETWEEN 2 AND 9
PM CDT TODAY ACROSS FAR WESTERN NORTH TEXAS AND FAR WESTERN
OKLAHOMA...MAINLY ALONG AND WEST OF A GAGE TO SEYMOUR LINE. DUE
TO MARGINAL WINDS AND SOME UNCERTAINTY WITH HUMIDITY LEVELS...HELD
OFF WITH A RED FLAG WARNING...BUT WILL CLOSELY MONITOR.
MBS
&&
.PREV DISCUSSION... /ISSUED 647 AM CDT MON APR 8 2013/
AVIATION...
08/12Z TAFS...PRIMARILY MVFR CIGS WITH INCREASING SOUTHERLY WIND
THROUGH THE DAY INTO TONIGHT. MVFR CONDITIONS FOR A FEW HOURS
EARLY THIS MORNING ACROSS SOUTHWEST OKLAHOMA AND KSPS BUT EXPECT
MOST OF CIGS TO SHIFT JUST EAST OF THOSE TERMINALS AFTER 15Z AND
RETURN AFTER 02Z. WEST-CENTRAL/NW OKLAHOMA TERMINALS WILL HAVE TO
DEAL WITH MVFR/IFR CONDITIONS EARLY IN FORECAST PERIOD NEAR AND
JUST NORTH OF WARM FRONT. FRONT WILL MAKE SLOW PROGRESS NORTHWARD
THIS MORNING WITH IMPROVING CONDITIONS AFTER 15-18Z. WILL NOT
INCLUDE TSRA IN ANY TERMINAL DUE TO VERY ISOLATED /IF ANY/ NATURE
LATER TODAY.
PREV DISCUSSION... /ISSUED 437 AM CDT MON APR 8 2013/
DISCUSSION...
STRONG CAP EXPECTED TO KEEP THUNDERSTORM CHANCES VERY LOW AGAIN
TODAY WITH ANY ISOLATED DEVELOPMENT NEAR DRYLINE/WARM FRONT OVER
FAR WEST/NORTHWEST OKLAHOMA. DEWPOINTS WILL BE SLIGHTLY HIGHER
TODAY AND LATEST MODELS INDICATE MORE IN THE WAY OF LOW-LEVEL
CONVERGENCE...BUT CAP WILL REMAIN QUITE STRONG. SCATTERED STORMS
THAT FIRED AROUND THE TULSA AREA FORMED ON NOSE OF LOW LEVEL JET
AND 800-700MB TIGHT BAROCLINIC ZONE. THIS ACTIVITY AND OTHER
ASSOCIATED WITH SAID TEMP GRADIENT SHOULD STAY NORTH AND EAST OF
CWA THIS MORNING.
LOW POPS WILL BE SEEN OVER A SMALL AREA OF WESTERN/NORTHERN
OKLAHOMA LATE TODAY INTO THIS EVENING WITH QUICK INCREASE IN POPS
TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING. ALTHOUGH WE CANNOT
RULE OUT A FEW STORMS IN WARM SECTOR NEAR/EAST OF DRYLINE
TUESDAY...PRIMARY FOCUS FOR WIDESPREAD THUNDERSTORMS WILL BE
STRONG COLD FRONT THAT WILL MOVE INTO NORTHWEST OKLAHOMA LATE
TUESDAY AFTERNOON AND MOVE QUICKLY SOUTHEAST OVER REGION. ALTHOUGH
SIGNIFICANT WEATHER WILL BE SEEN WITH ANY STORM THAT HAPPENS TO
DEVELOP AHEAD OF FRONT...PRIMARY IMPACTS FROM SEVERE WEATHER WILL
BE WIND/HAIL ASSOCIATED WITH SQUALL LINE. POTENTIAL FOR SEVERE
WEATHER EXPECTED TO DECREASE WITH ANY POST-FRONTAL STORMS LATE
TUESDAY NIGHT AND WEDNESDAY. MUCH COLDER AIR WILL FILTER IN BEHIND
FRONT...AND GIVEN PROGD GRADIENT AND COLD ADVECTION...WIND
ADVISORY MAY BE NEEDED TUESDAY NIGHT/EARLY WEDNESDAY MORNING.
SPEAKING OF COLD AIR...WE WILL MENTION SOME RAIN/SNOW AND SNOW
AREAS ACROSS PORTIONS OF NORTHERN AND WESTERN OKLAHOMA TUESDAY
NIGHT AND EARLY WEDNESDAY MORNING. DESPITE SOME AGGRESSIVE SNOW
OUTPUT FROM MODELS...PRECIP WILL BE ENDING AND INTRUSION OF DRY
AIR EXPECTED TO PRECLUDE ANY SIGNIFICANT ACCUMS. FREEZE LIKELY
ACROSS AT LEAST NORTHWEST THIRD OR SO OF OKLAHOMA WEDNESDAY
MORNING AND POSSIBLY OVER A MUCH LARGER AREA THURSDAY MORNING.
GIVEN THAT WE HAVE PASSED THE CLIMO FOR FREEZES OVER CENTRAL AND
SOUTHERN OKLAHOMA/NORTHERN TEXAS...FREEZE WARNINGS MAY BE
WARRANTED.
REINFORCING SHOTS OF COOLER AIR EXPECTED THROUGH FRIDAY WITH
WARMUP INCREASING OVER WEEKEND. MODELS SOMEWHAT INCONSISTENT WITH
PRECIP POTENTIAL LATE FRIDAY AND SATURDAY WITH NORTHWEST FLOW
SYSTEM...BUT WITH RUN TO RUN CONSISTENCY LESS THAN DESIRED DID NOT
INTRO POPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 77 64 75 36 / 0 10 20 70
HOBART OK 87 62 77 32 / 20 20 30 50
WICHITA FALLS TX 84 63 81 38 / 0 10 20 60
GAGE OK 84 61 71 25 / 20 10 20 30
PONCA CITY OK 75 63 74 36 / 0 10 30 70
DURANT OK 74 64 77 52 / 10 10 10 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1132 AM EDT MON APR 8 2013
.SYNOPSIS...
A WARM FRONT IS LIFTING NORTHWARD ACROSS CENTRAL PA. SCATTERED
SHOWERS AND ISOLATED AFTERNOON THUNDERSTORM WILL BE
POSSIBLE...MAINLY ACROSS THE NORTHWESTERN MOUNTAINS. ABOVE NORMAL
TEMPERATURES ARE EXPECTED TO PREVAIL FOR MUCH OF THE COMING WEEK.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE...MAINLY OVER
NORTHERN PENNSYLVANIA INTO THURSDAY. A COLD FRONT WILL PASS
THROUGH LATE IN THE WEEK WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS. THE STORM WILL USHER IN COOLER AND DRIER CONDITIONS
FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
THE FRONT IS MOST LIKELY LIFTING THROUGH THE WESTERN MOUNTAINS
RIGHT NOW AND DEWPOINTS ARE MOVING UPWARD. SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON WHILE THE WARM FRONT
PUSHES ACROSS. WINDS ARE INCREASING THROUGH THE MID-LAYERS THROUGH
THE AFTERNOON AND LAST THIS EVENING AS A LL JET OF ABOUT 50KTS
NOSES INTO THE NWRN MTS. WILL HOLD OFF ON A MENTION OF GUSTY WINDS
OR HAIL AT THIS POINT...BUT NEW INFO FROM RUC/RAP AND HRRR WILL
AID WITH THIS DECISION LATER TODAY. THE COVERAGE MAY ALSO BE
RATHER SPARSE. WILL HOLD POPS IN THE HIGH CHC/LOW LIKELY RANGE
UNTIL SUNSET.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM TUESDAY/...
TSRA STILL POSSIBLE IN THE EVENING AND MID LEVEL JET REMAINS AT
ABOUT 50KTS ALONG THE NY BORDER.
EVENING CONVECTION MAY CONTINUE THROUGH MID TO LATE EVENING AS
ADDITIONAL SHORTWAVES FLATTEN THE SHORTWAVE RIDGE ACROSS THE
REGION AND DEEP LAYER MOISTURE OF 1"+ IS REPLACED BY <0.75" PW BY
06Z. BOUNDARY LAYER CONVERGENCE IS RATHER ROBUST WITH 40+ KT 850
MB WINDS PROPAGATING EASTWARD ACROSS THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ THIS EVENING. ACTIVITY SHOULD DWINDLE QUICKLY AFTER
MIDNIGHT WITH THE ARRIVAL OF DRIER AIR ALOFT AND DECREASING
BOUNDARY LAYER CONVERGENCE BETWEEN 06Z AND 12Z TUE. OVERNIGHT MINS
WILL BE GENERALLY MILD...RANGING FROM THE UPPER 40S NORTHWEST TO
THE MID 50S SOUTHEAST.
TUESDAY WILL BE SIMILAR TO MONDAY WITH A MOISTURE BOUNDARY DRAPED
ACROSS THE SOUTH CENTRAL MOUNTAINS...WHERE PW WILL RANGE FROM 0.5"
ACROSS THE CENTRAL MOUNTAINS TO ABOUT 0.85 ALONG THE PA/MD BORDER
TO START THE DAY. ANOTHER NORTHWARD SURGE OF MOISTURE WILL TAKE
PLACE AS YET ANOTHER SFC TROF LIFTS NEWD THROUGH THE CENTRAL AND
EASTERN GREAT LAKES...TOUCHING OFF ANOTHER ROUND OF SHOWERS AND
LOCAL THUNDERSTORMS TUESDAY AFTERNOON. IT WILL BE MILDER STILL
WITH HIGHS RANGING FROM THE MID 60S NORTH TO THE MID TO UPPER 70S
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
WARM CONDITIONS FOR MUCH OF THE PERIOD TUE EVE INTO THU...AS MUCH
OF CENTRAL PA WILL BE IN THE WARM AIR. NOW LOOKS LIKE MUCH OF THE
RAIN WILL BE MUCH FURTHER NORTH THIS WEEK.
IT WILL BE INTERESTING TO SEE HOW WARM WE GET BY MID WEEK...GIVEN
THE CHANGE IN THE UPPER LVL PATTERN. WILL SEE HOW THIS PLAYS OUT
ESPECIALLY GIVEN THE RECENT HIGH LATITUDE BLOCKING AND COLD SPELL.
TEMPS COULD PUSH UPPER 80S SOUTHERN PA BY WED...GIVEN 850 MB
TEMPS.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
WARM FRONT LIFTING NORTHWARD ACROSS THE REGION TODAY WILL ALLOW
SCT TSRA TO FORM...BUT THEY WILL NOT BE WIDESPREAD ENOUGH TO
MENTION IN THE TAFS JUST YET. WILL MENTION SHRA FOR MOST
SITES...BUT MDT/LNS SHOULD NOT HAVE ANY SHRA. CIGS/VISBYS WILL
REMAIN VFR...EXCEPT IN THE FEW SHRA THAT DO HAPPEN TO PASS RIGHT
OVER THE AIRFIELDS. KBFD IS MOST-LIKELY TO SEE A REDUCTION TO
MVFR...MAINLY BETWEEN 21Z AND 03Z. BUT FORCING REMAIN WELL TO THE
NORTH OF THE AREA THIS AFTN/TONIGHT. WINDS DO GET STRONG AT FL050
WITH UP TO 50KTS ALONG THE NY BORDER. THIS COULD CREATE SOME GUSTS
IN THE STORMS. BUT...AGAIN...THESE SHOULD BE ISOLD/SCT IN
COVERAGE.
.OUTLOOK...
TUE...EARLY AM LOW CIGS POSS W MTNS. ISOLD TSRA IMPACTS POSS NORTH.
WED...EARLY AM LOW CIGS POSS NW MTNS. ISOLD TSRA IMPACTS POSS NORTH.
THU...CHC OF PM TSRA IMPACTS.
FRI...AM RAIN/LOW CIGS POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO/DEVOIR
LONG TERM...MARTIN/STEINBUGL
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
803 AM EDT MON APR 8 2013
.SYNOPSIS...
A STALLED SURFACE FRONT ALONG THE TURNPIKE THIS MORNING WILL LIFT
NORTHWARD AS A WARM FRONT ACROSS CENTRAL PA TODAY. SCATTERED
SHOWERS AND ISOLATED AFTERNOON THUNDERSTORM WILL BE POSSIBLE.
ABOVE NORMAL TEMPERATURES ARE EXPECTED TO PREVAIL FOR MUCH OF THE
COMING WEEK. SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE...MAINLY OVER NORTHERN PENNSYLVANIA INTO THURSDAY. A
COLD FRONT WILL PASS THROUGH LATE IN THE WEEK AND USHER IN COOLER
AND DRIER CONDITIONS FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
--SHRA OVER THE TURNPIKE PLACE THE FRONT ALOFT JUST ABOUT THERE
THIS MORNING. THE FRONT SHOULD START TO LIFT NORTHWARD OVER THE
WESTERN COUNTIES. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE THIS AFTERNOON WHILE THE WARM FRONT PUSHES ACROSS. WINDS
ARE INCREASING THROUGH THE MID-LAYERS THROUGH THE AFTERNOON AND
LAST THIS EVENING AS A LL JET OF ABOUT 50KTS NOSES INTO THE NWRN
MTS. WILL HOLD OFF ON A MENTION OF GUSTY WINDS OR HAIL AT THIS
POINT...BUT NEW INFO FROM RUC/RAP AND HRRR WILL AID WITH THIS
DECISION LATER TODAY. THE COVERAGE MAY ALSO BE RATHER SPARSE. WILL
HOLD POPS IN THE HIGH CHC/LOW LIKELY RANGE UNTIL SUNSET.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/...
TSRA STILL POSSIBLE IN THE EVENING AND MID LEVEL JET REMAINS AT
ABOUT 50KTS ALONG THE NY BORDER.
EVENING CONVECTION MAY CONTINUE THROUGH MID TO LATE EVENING AS
ADDITIONAL SHORTWAVES FLATTEN THE SHORTWAVE RIDGE ACROSS THE
REGION AND DEEP LAYER MOISTURE OF 1"+ IS REPLACED BY <0.75" PW BY
06Z. BOUNDARY LAYER CONVERGENCE IS RATHER ROBUST WITH 40+ KT 850
MB WINDS PROPAGATING EASTWARD ACROSS THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ THIS EVENING. ACTIVITY SHOULD DWINDLE QUICKLY AFTER
MIDNIGHT WITH THE ARRIVAL OF DRIER AIR ALOFT AND DECREASING
BOUNDARY LAYER CONVERGENCE BETWEEN 06Z AND 12Z TUE. OVERNIGHT MINS
WILL BE GENERALLY MILD...RANGING FROM THE UPPER 40S NORTHWEST TO
THE MID 50S SOUTHEAST.
TUESDAY WILL BE SIMILAR TO MONDAY WITH A MOISTURE BOUNDARY DRAPED
ACROSS THE SOUTH CENTRAL MOUNTAINS...WHERE PW WILL RANGE FROM 0.5"
ACROSS THE CENTRAL MOUNTAINS TO ABOUT 0.85 ALONG THE PA/MD BORDER
TO START THE DAY. ANOTHER NORTHWARD SURGE OF MOISTURE WILL TAKE
PLACE AS YET ANOTHER SFC TROF LIFTS NEWD THROUGH THE CENTRAL AND
EASTERN GREAT LAKES...TOUCHING OFF ANOTHER ROUND OF SHOWERS AND
LOCAL THUNDERSTORMS TUESDAY AFTERNOON. IT WILL BE MILDER STILL
WITH HIGHS RANGING FROM THE MID 60S NORTH TO THE MID TO UPPER 70S
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
WARM CONDITIONS FOR MUCH OF THE PERIOD TUE EVE INTO THU...AS MUCH
OF CENTRAL PA WILL BE IN THE WARM AIR. NOW LOOKS LIKE MUCH OF THE
RAIN WILL BE MUCH FURTHER NORTH THIS WEEK.
IT WILL BE INTERESTING TO SEE HOW WARM WE GET BY MID WEEK...GIVEN
THE CHANGE IN THE UPPER LVL PATTERN. WILL SEE HOW THIS PLAYS OUT
ESPECIALLY GIVEN THE RECENT HIGH LATITUDE BLOCKING AND COLD SPELL.
TEMPS COULD PUSH UPPER 80S SOUTHERN PA BY WED...GIVEN 850 MB
TEMPS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHOWERS HAVE CEASED AS ANY INSTABILITY HAS FADED OVERNIGHT INTO
TOMORROW.
THE BIGGEST AVIATION CONCERN IN THE NEAR TERM WILL BE THE
POSSIBILITY OF SOME LATE NIGHT FOG ACROSS SOUTHERN PA. MDL DATA
SHOWING A TONGUE OF RELATIVELY MOIST AIR IN VICINITY OF DYING COLD
FRONT LAYING OUT ACROSS SOUTHERN PA LATE TONIGHT. THIS
MOISTURE...COMBINED WITH DIMINISHING WINDS...COULD SET THE STAGE
FOR PATCHY RADIATION FOG ARND DAWN ACROSS SOUTHERN PA...ESP IN
THOSE FEW SPOTS THAT RECEIVE RAINFALL THIS EVENING. CONFIDENCE NOT
HIGH ENOUGH TO MENTION IN TAFS YET...BUT WILL HAVE TO MONITOR
OVERNIGHT.
GUSTY SW WINDS AHEAD OF THE CDFRNT EARLY THIS EVENING WILL WEAKEN
AS THE DYING FRONT WASHES OUT ACROSS SOUTHERN PA LATER THIS
EVENING.
ANY EARLY FOG SHOULD LIFT SHORTLY AFTER SUNRISE MONDAY. FOCUS
WILL THEN SHIFT TOWARD THE LIKELIHOOD OF SCT AFTN CONVECTION
ASSOCIATED WITH FRONTAL BOUNDARY LIFTING BACK NORTH ACROSS THE
REGION AS A WARM FRONT. AN AFTN SHRA/TSRA COULD BRIEFLY LOWER
VSBYS...DESPITE WIDESPREAD VFR CONDS.
.OUTLOOK...
TUE...EARLY AM LOW CIGS POSS W MTNS. ISOLD TSRA IMPACTS POSS NORTH.
WED...EARLY AM LOW CIGS POSS NW MTNS. ISOLD TSRA IMPACTS POSS NORTH.
THU...CHC OF PM TSRA IMPACTS.
FRI...AM RAIN/LOW CIGS POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DEVOIR
LONG TERM...MARTIN/STEINBUGL
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
654 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
437 AM UPDATE...NOTICED THAT BOTH THE 08.00Z ECMWF AND 08.00Z/06Z
NAM INDICATE A DRY SLOT COMING THROUGH ALOFT TO SCOUR OUT THE ICE IN
THE CLOUDS FOR WEDNESDAY NIGHT AND THURSDAY. IF THIS COMES TO
FRUITION...WE MAY BE DEALING MORE WITH RAIN / FREEZING RAIN VERSUS
SNOW...AND THUS BACK TO WONDERING ABOUT OBJECT TEMPERATURES.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 654 AM CDT MON APR 8 2013
A LOW PRESSURE SYSTEM WILL PRODUCE SHOWERS AT KLSE THROUGH
08.15Z. IN THE WAKE OF THIS FRONT...SUBSIDENCE WILL BUILD ACROSS
THE REGION. THE BUFKIT SOUNDINGS SUGGEST THAT A MVFR DECK WILL
BECOME TRAPPED UNDER THE SUBSIDENCE INVERSION. HOWEVER THINKING
THAT THE MODELS MIGHT BE HAVING ISSUES WITH THE LOW LEVEL MOISTURE
FROM THE DENSE FOG ACROSS SOUTHWEST MINNESOTA AND NORTHWEST IOWA.
IF THIS WAS EARLIER IN THE NIGHT WOULD EXPECT THAT OUR AREA WOULD
ALSO SEE DENSE FOG AND LOW CEILINGS. HOWEVER WITH THE SUN ALREADY
UP...THINKING THAT THE PROBABILITIES FOR THIS OCCURRING IS MUCH
LOWER...SO OPTED TO GO MORE OPTIMISTIC AND JUST WENT WITH SOME
SCATTERED MVFR CLOUDS.
FOR TONIGHT...ANOTHER LOW PRESSURE SYSTEM WILL MOVE INTO THE
REGION. WENT WITH THE SLOWER GFS AND ECMWF SOLUTIONS...SO DELAYED
THE ONSET OF THE RAIN SHOWERS BY ABOUT 6 HOURS IN THE TAFS. THIS
WOULD MEAN ASTART OF AROUND 09.08Z FOR KRST AND 09.10Z FOR KLSE.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1053 AM MDT MON APR 8 2013
.UPDATE...VERY COMPLEX WEATHER SCENARIO FOR THE FORECAST AREA
STILL MAKING FOR A DIFFICULT FORECAST. LATEST WATER VAPOR LOOP
SHOWS CONSIDERABLE DIGGING STILL OCCURRING AND 12Z RAOBS/RUC
ANALYSIS WOULD SUGGEST A 150 KT JET DIVING DOWN THE BACK SIDE OF
THIS TROUGH SO FURTHER DIGGING LIKELY. THE 12Z MODEL RUNS HAVE
TRENDED BACK A LITTLE FARTHER SOUTH AND THIS SEEMS GOOD
CONSIDERING THE WATER VAPOR IMAGERY. AT THE SAME TIME...COLD FRONT
IS ALREADY BARRELING SOUTHWARD THROUGH EASTERN WYOMING AND SHOULD
REACH DENVER BY/SHORTLY BEFORE 00Z GIVEN STRONG PRESSURE RISES
BEHIND THE FRONT...AND ONLY BECAUSE OF SOME SLOWING DUE TO DAYTIME
HEATING/MIXING AHEAD OF THE FRONT OTHERWISE IT WOULD BE HERE
SOONER. LATEST 12Z NAM SHOWS A STRONG BARRIER JET FORMING THIS
EVENING AS COLD AIR PLUNGES SOUTHWARD ALONG THE FRONT RANGE. THIS
COULD LEAD TO A PERIOD OF CONVECTIVE AND HEAVY SNOWFALL AS RAIN
QUICKLY CHANGES OVER TO SNOW...WITH A COUPLE HOURS OF NEAR
BLIZZARD CONDITIONS POSSIBLE ALL DEPENDING ON WHETHER COLD AIR
ARRIVAL COINCIDES WITH CONVECTION.
WITH REGARD TO SEVERE THREAT...LITTLE CHANGE THERE TOO WITH
POSSIBLE LARGE HAIL AND TORNADO THREAT MAINLY ALONG/EAST OF A LINE
FROM FORT MORGAN TO LIMON. HIGHEST PROBABILITY WOULD LIKELY SHIFT
TOWARD AKRON AND LIMON WITH FASTER ARRIVAL OF FRONT. STILL SOME
CIRRUS TO OVERCOME BUT TEMPS ALREADY IN THE LOWER 60S AND IF WE
REACH 70F THEN STORMS WILL POP.
FOR LATER TONIGHT...THE SNOW COULD VERY WELL DECREASE ESPECIALLY
OVER THE SOUTHERN HALF OF THE FORECAST AREA OVERNIGHT AS A DRY
SLOT WORKS NORTHWARD...BUT SHOULD SPREAD BACK SOUTH/SOUTHEAST OVER
NORTHEAST COLORADO TUESDAY MORNING AS UPPER LOW TRACKS TOWARD THE
FOUR CORNERS. WATCHES HAVE BEEN UPGRADED TO WARNINGS IN AREAS OF
HIGHEST CONFIDENCE WHILE WATCHES WILL CONTINUE OVER THE FAR
EASTERN PLAINS DUE TO HIGHER POTENTIAL FOR DRY SLOT PERSISTING
THERE. WILL GO WITH BLIZZARD WARNINGS FOR POINTS JUST
EAST/SOUTHEAST OF DENVER WHERE STRONGER WINDS WILL BE MORE
PERSISTENT.
&&
.AVIATION...SOUTHERLY WINDS WERE A LITTLE DELAYED AT KDEN.
OTHERWISE TAFS WILL BE PRETTY MUCH UNCHANGED. WILL SUGGEST HEAVIER
SNOW POTENTIAL FOR A COUPLE HOURS 03Z-06Z THIS EVENING...THEN SOME
DECREASE LATE...AND INCREASE AGAIN BY TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 408 AM MDT MON APR 8 2013/
SHORT TERM...FOR TODAY AND TONIGHT...A COMPLEX WEATHER PATTERN IS
SETTING UP ACROSS THE REGION. PACIFIC STORM IS DIGGING SOUTHEAST
ACROSS NORTHERN CALIFORNIA AT THIS TIME. LATEST MODELS HAVE BEEN
SHOWING A SLIGHT SHIFT NORTH IN THE STORM TRACK. BY 12 TUESDAY
MORNING...THE UPPER LEVEL LOW WILL BE CENTER JUST WEST OF THE FOUR
CORNERS WITH THE SURFACE LOW NEAR THE OKLAHOMA PAN HANDLE.
STILL A GOOD AMOUNT OF UNCERTAINTY ON THE PLACEMENT OF THE DRY LINE
AND WHEN THE COLD FRONT WILL PUSH THROUGH THE AREA. STILL APPEARS
THE DRY LINE WILL BE ROUGHLY ALONG A LINE FROM FORT MORGAN TO LIMON.
HOWEVER...THE LATEST RAP HAS IT NEAR DENVER EARLY THIS EVENING
BEFORE THE COLD FRONT PUSHES THROUGH. BEST CHANCE FOR THUNDERSTORMS
WILL OCCUR EAST OF WHERE THE DRY LINE SETS UP. DUE TO STRONG
SHEAR...SUPERCELLS WILL BE POSSIBLE WITH LARGE HAIL. SINCE LOW LEVEL
SHEAR WILL BE STRONG...TORNADOES WILL ALSO BE POSSIBLE WITH ANY
STRONG STORM THAT DEVELOPS.
MODELS ARE COMING INTO BETTER AGREEMENT OVER THE LAST HOUR IN
SHOWING THE COLD FRONT ENTERING COLORADO LATE THIS AFTERNOON AND
PUSHING THROUGH THE DENVER AREA AROUND 00Z. NORTH TO NORTHEAST
UPSLOPE WINDS BEHIND THE FRONT COMBINED WITH A STRONG DIFFLUENT FLOW
ALOFT WILL GENERATE LIFT THROUGH OUT THE AIRMASS. PRECIPITATION WILL
START OFF AS RAIN AND CHANGE OVER TO SNOW AS COLD AIR MOVES INTO THE
AREA. FOR THE DENVER AREA...WOULD EXPECT THE CHANGE OVER TO SNOW
AROUND MID TO LATE EVENING.
THE AREA IS ON THE EDGE OF THE HEAVIER SNOW. IF THIS SYSTEM KEEPS
TRENDING NORTH...THE HEAVY SNOW MAY END UP JUST TO OUR NORTH. ALSO
WHEN THE RAIN CHANGES TO SNOW WILL PLAY A BIG ROLE ON HOW MUCH SNOW
ACCUMULATES. THEREFORE WILL CONTINUE WITH THE WINTER STORM WATCH AT
THIS TIME AND NOT UPGRADE TO ANY WARNINGS.
DID INCREASE TEMPERATURES INTO THE MID TO UPPER 60S FOR MOST OF
NORTHEAST COLORADO. AIRMASS WILL LIKELY BE WARM ENOUGH TO SUPPORT
LOWER 70S...BUT EXPECT THE MOSTLY CLOUDY SKIES TO TAKE OFF A FEW
DEGREES FROM REACHING OUR FULL POTENTIAL.
LONG TERM...AS MENTIONED A FEW DAYS AGO IT NEVER FAILS THAT
SOMETHING WILL MANY TIMES MESS UP A DECENT STORM AND IT APPEARS
THIS TIME WILL BE NO DIFFERENT. ALTHOUGH THERE IS GOOD AGREEMENT
THAT A CLOSED UPPER LEVEL LOW WILL BE NR THE FOUR CORNERS BY
12Z...BY TUE EVENING THE MODELS PRETTY MUCH SPLIT THE SYSTEM WITH
THE MAIN PIECE OF ENERGY LIFTING NE INTO EITHER SERN WY OR WRN
NEBRASKA. THE ECMWF TRACKS THIS FEATURE WEST OF NERN CO WHILE THE
NAM AND GFS HAVE IT MOVING ACROSS NERN CO ON TUE. THERE IS STILL
DECENT UPSLOPE TUE MORNING WITH FAVORABLE QG ASCENT SO STILL CAN
NOT RULE OUT SOME HEAVIER SNOW THRU MID TO LATE MORNING IN AND NR
THE FOOTHILLS AND POSSIBLY OVER THE PALMER DIVIDE. MEANWHILE OVER
THE PLAINS OF NERN CO A POTENTIAL DRY SLOT MAY DEVELOP WHICH WOULD
LIMIT HEAVY SNOW POTENTIAL EAST OF A STERLING TO LIMON LINE THRU
THE AFTN HOURS. FOR NOW WILL LEAVE WATCHES AS IS AND LET THE DAY
SHIFT SEE IF THE MODELS CAN COME TO A CONSENSUS ON WHERE BEST
HEAVY SNOWFALL POTENTIAL MAY OCCUR. WINDS WILL BE GUSTY ON TUE SO
STILL EXPECT AREAS OF BLOWING SNOW. HIGHS WILL BE WELL BLO NORMAL
WITH READINGS NOT GETTING OUT OF THE 20S.
BY TUE NIGHT INTO WED THE UPPER LEVEL LOW IS FCST TO STALL OVER
WRN NEBRASKA. THE ECMWF AND GFS SHOW DRIER AIR SPREADING OVER NERN
CO ALTHOUGH THERE IS STILL SOME MOISTURE IN THE MTNS WHICH MAY
LEAD TO A CHC OF LIGHT OROGRAPHIC SNOWS. MEANWHILE GUSTY NLY
WINDS WILL STILL OCCUR OVER THE PLAINS OF NERN CO THRU THE AFTN.
HIGHS ON WED DUE TO LINGERING COLD TEMPS IN THE 850-700 MB LAYER
WILL ONLY BE IN THE 30S OVER NERN CO.
FOR THU THE UPPER LEVEL WILL MOVE EASTWARD WITH NWLY FLOW ALOFT
OVER NRN CO. A DISTURBANCE IN THIS FLOW WILL MOVE ACROSS NRN CO
LATE THU AFTN OR EVENING. CROSS- SECTIONS SHOW MOISTURE
INCREASING THE MTNS WITH DECENT LAPSE RATES SO MAY SEE A GOOD CHC
OF SNOW IN THE AFTN AND EVENING. OVER NERN CO ANOTHER WK FNT IS
FCST TO MOVE ACROSS THE AREA BY EVENING BRIEFLY ENHANCING UPSLOPE
FLOW. THIS IS THE DISTURBANCE MOVES ACROSS ALONG WITH A DECENT
UPPER LEVEL JET THIS COULD LEAD TO A CHC OF PCPN LATE THU AFTN
INTO THU EVENING. WILL KEEP HIGHS ON THU WILL IN THE MID TO UPPER 40S
ACROSS THE PLAINS.
BY FRI THE FLOW ALOFT WILL REMAIN NWLY WITH QUITE A BIT OF
MOISTURE EMBEDDED IN THE FLOW. THE ECMWF AND GFS SHOW ANOTHER
POTENTIAL DISTURBANCE TRACKING ACROSS THE AREA FRI AFTN INTO FRI
EVENING WITH ANOTHER WEAK SURGE MOVING ACROSS NERN CO. THUS SHOULD
SEE ANOTHER CHC OF SNOW IN THE MTNS WITH AT LEAST A SLIGHT CHC OF
PCPN AT LOWER ELEVATIONS. AS FOR HIGHS WILL HAVE READINGS IN THE
UPPER 40S TO LOWER 50S OVER NERN CO.
FOR THE WEEKEND RIGHT NOW THE FLOW ALOFT IS SUPPOSED TO BECOME
MORE ZONAL WHICH WOULD LEAD TO WARMER TEMPERATURES AND DRIER
CONDITIONS.
AVIATION...SOUTH TO SOUTHEAST WINDS WILL PREVAIL THROUGH THE DAY
UNTIL A COLD FRONT PUSHES THROUGH AROUND 23-00Z. WINDS WILL TURN
NORTHERLY BEHIND IT. WILL BE A CHANCE FOR THUNDERSTORMS AFTER
21Z...BUT THE BEST CHANCE WILL BE OVER FAR EASTERN COLORADO. RAIN
WILL DEVELOP AFTER 00Z TONIGHT AND CHANGE TO SNOW AROUND 04-05Z.
SNOW WILL BE HEAVY AT TIMES. VISIBILITY WILL BE REDUCED TO QUARTER
MILE OR LESS AT TIMES DUE TO SNOW AND BLOWING SNOW. THE HEAVIEST
SNOW IS EXPECTED TO FALL FROM 06-18Z TUESDAY. SNOWFALL TOTALS AT THE
DENVER AIRPORTS ARE EXPECTED TO RANGE FROM 6 TO 12 INCHES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY EVENING FOR
COZ046-048>051.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT TUESDAY
FOR COZ033>036.
WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 PM MDT TUESDAY
FOR COZ038>040-042>044.
BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 PM MDT TUESDAY FOR
COZ041-045.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....RPK
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
315 PM EDT MON APR 8 2013
.DISCUSSION...
TONIGHT-TUESDAY...
LITTLE CHANGE IN THE CURRENT SYNOPTIC PATTERN. RIDGE AXIS OVER THE W
ATLC/NRN GULF COAST WILL MAINTAIN A STEADY E/SE LOW LVL FLOW ACRS
THE FL PENINSULA...AS WELL AS A STRONG SUBSIDENCE INVERSION IN THE
H85-H70 LYR. LATEST RAP ANALYSIS SHOWS A SINKING AIRMASS ACRS THE
REGION WITH POSITIVE OMEGA VALUES IN THE H85-H30 LYR AND NEGATIVE
DIVERGENCE VALUES IN THE H30-H20 LYR...NO SIG MID LVL VORT MAXES TO
SPEAK OF.
THE ONSHORE LOW LVL FLOW WILL TAP A RESPECTABLE AMOUNT OF LOW LVL
MOISTURE JUST OFFSHORE (H100-H85 MEAN RH AOA 80PCT). HOWEVER... NONE
OF THE LOW-TOPPED SHRAS THE KMLB RADAR HAS BEEN DETECTING OVER THE
GULF STREAM HAVE BEEN ABLE TO SURVIVE FOR LONG ONCE THEY MOVE INTO
THE COOLER SHELF WATERS. IN ORDER TO DO SO WITH A SUBSIDENCE
INVERSION CAPPING THE AIRMASS BLO 7KFT AND THE ABSENCE OF MID/UPR
LVL FORCING...LOW LVL WINDS WOULD NEED TO BE A GOOD 15KTS AND ALMOST
NORMAL TO THE COAST. ANTICIPATED POSITION OF THE RIDGE WILL NOT
ALLOW THIS TYPE OF WIND FIELD TO DVLP. CONTINUED DRY FCST.
PERSISTENT ONSHORE FLOW WILL CONTINUE TO GENERATE COOLER DAYS/WARMER
NIGHTS ALONG THE COAST THAN THE INTERIOR. MINS IN THE M60S ALONG THE
COAST...L60S INTERIOR. MAXES IN THE L80S ALONG COAST...M80S INTERIOR.
WED...THE RIDGING ALOFT SHOULD BEGIN TO WEAKEN AND LOW LEVEL FLOW
WILL TURN TO THE SOUTHEAST. HIGHER MOISTURE VALUES WILL BRING A
SLIGHT CHANCE OF SHOWERS. TEMPS WILL BE ABOVE NORMAL WITH HIGHS
IN THE LOWER 80S ALONG THE COAST AND MID 80S INLAND. OVERNIGHT
LOWS SHOULD BE EVEN MORE ABOVE NORMAL...IN THE MID TO UPPER 60S.
THU-FRI...(MODIFIED PREVIOUS DISC) RECENT GUIDANCE COMING INTO
BETTER AGREEMENT WITH THE TIMING OF THE NEXT FRONT. THE 12Z GFS
REMAINS SLIGHTLY FASTER THAN THE ECMWF BUT NOT AS MUCH SO AS
RECENT CYCLES. PRE-FRONTAL MOISTENING FROM INCREASING SOUTHERLY
WINDS WILL BOOST POPS...REACHING 40 PERCENT ON FRI. TEMPS WILL
ALSO INCREASE WITH MID 80S AREAWIDE BOTH DAYS AND SOME UPPER 80S
TO AROUND 90 OCCURRING IN THE SOUTH.
SAT-MON...NCEP INDICATES WEAKENING FRONTAL BOUNDARY STALLING
OVER THE SOUTH PENINSULA BY SUNDAY AND WASHING OUT BY MON. THIS
LOOKS TO BE A GOOD COMPROMISE BETWEEN FASTER GFS AND SLOWER
ECMWF...GIVEN THAT FRONTS OFTEN DIE OUT SOMEWHERE OVER FLORIDA
THIS TIME OF THE YEAR.
&&
.AVIATION...
THRU 09/18Z...PREVAILING VFR ALL SITES. BTWN 09/08Z-09/13Z...LCL
MVFR CIGS IN BR.
&&
.MARINE...
TONIGHT-TUESDAY...RIDGE AXIS OVER THE ATLC WILL MAINTAIN A GENTLE TO
MODERATE E/SE BREEZE ACRS THE LCL ATLC...AS WELL AS A 3-4FT ERLY
SWELL...DOMINANT PDS 9-10 SEC. COMBINED SEAS 3-4FT NEARSHORE AND
4-5FT OFFSHORE...BCMG 4-5FT AREAWIDE.
WED-FRI...INITIALLY ONSHORE FLOW WILL OCCUR AS RIDGE AXIS REMAINS
TO OUR NORTH. SPEEDS INCREASE TO 15 KNOTS AND GUSTY WED. FLOW LOOKS
TO BE SOUTHEAST-SOUTH ON THU AT 15-20 KNOTS THEN SOUTH-SOUTHWEST
15-20 KNOTS FRI. A SLIGHT CHANCE FOR STORMS EXISTS FOR THU AND
FRI AND A CHANCE FOR AFTERNOON-EVENING STORMS MOVING OFF THE
MAINLAND EXISTS.
&&
.FIRE WEATHER...
E/SE SFC/TRANSPORT FLOW BCMG S/SE THRU MIDWEEK...NO WIND/RH CONCERNS
ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 63 80 65 80 / 0 10 10 10
MCO 62 85 64 86 / 0 10 10 20
MLB 64 81 69 83 / 0 10 10 20
VRB 65 81 68 81 / 10 10 10 20
LEE 61 85 63 85 / 0 0 10 20
SFB 62 85 64 85 / 0 10 10 20
ORL 62 85 65 85 / 0 10 10 20
FPR 65 81 69 82 / 10 10 10 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...BRAGAW
LONG TERM....PENDERGRAST
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1248 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 953 AM CDT MON APR 8 2013
MCV AND THE ASSOCIATED PRECIPITATION IS STARTING TO MOVE ACROSS
LAKE MICHIGAN AND THE DOWNWARD MOTION BEHIND THE MCV HAS ENDING
THE RAIN ACROSS THE AREA. A RESPECTABLE OUTFLOW BOUNDARY LIES JUST
SOUTH OF THE CWFA AND THERE IS A VORT MAX CROSSING THE MISSOURI RIVER.
THE QUESTION NOW IS WILL PRECIPITATION REGENERATE THIS AFTERNOON.
IF THE RAP FCST SOUNDING TRENDS ARE CORRECT...THE CONVECTIVE
TEMPERATURE WILL SLOWLY INCREASE THROUGH LATE MORNING AND
AFTERNOON AND SHOULD BE HIGHER THAN THE FCST MAX TEMPERATURES.
THUS THE OUTFLOW BOUNDARY SOUTH OF THE CWFA SHOULD REMAIN QUIET.
WITH CONVECTIVE TEMPERATURES HIGHER THAN THE FCST MAX...THE
INCOMING VORT MAX SHOULD ONLY RESULT IN SOME PASSING CLOUDS. ..08..
UPDATE ISSUED AT 659 AM CDT MON APR 8 2013
HAVE JUST SENT OUT A QUICK UPDATE TO FRESHEN UP THE FORECAST FOR
RECENT RADAR TRENDS...TEMPERATURES AND WINDS. BAND OF RAINFALL IS
STILL ON TRACK TO MOVE OUT OF THE FORECAST AREA BY MID TO LATE
MORNING...WITH NO ADDITIONAL THUNDER.
ALSO UPDATED AVIATION SECTION BELOW.
&&
.SYNOPSIS...
ISSUED AT 330 AM CDT MON APR 8 2013
A NICE MCS IS ONGOING OVER THE FORECAST AREA THIS MORNING...WITH
A 40-50KT LOW LEVEL JET IMPINGING ON THE SOUTHWEST FLANK OF THE
SYSTEM...IN AN AREA OF VERY GOOD MID LEVEL CONVERGENCE AND A WEAK
850MB FRONT...AND BETTER SURFACE FRONT. MOST OF THE THUNDERSTORMS
ARE MOVING ACROSS MISSOURI THIS MORNING...WITH A BROAD AREA OF
RAIN AND EMBEDDED THUNDER ROTATING NORTHEAST ACROSS THE FORECAST
AREA. THE MCV WITH THIS MCS IS WHAT IS DRIVING SOME OF THE
EAST-NORTHEAST MOVEMENT...AND EXPECT THAT NEARLY ALL OF THE
FORECAST AREA WILL RECEIVE RAINFALL BEFORE THE EVENT IS OVER. THE
BEST RAINFALL RATES HAVE RANGED UP TO 4 TENTHS OF AN INCH PER
HOUR...BUT MORE LOCATIONS ARE RECEIVING BETWEEN 1 AND 3
TENTHS/HOUR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT MON APR 8 2013
TODAY THE MAIN CONCERN IS FOR HOW QUICKLY THIS MCS WILL MOVE EAST
OUT OF THE FORECAST AREA THIS MORNING. THEN...HAVE CONCERNS FOR
POSSIBLE CONVECTION ALONG THE FRONT DURING THE DAYTIME. AN
THEN...OUR NEXT MCS IS EXPECTED TONIGHT AS THE NEXT SHORTWAVE
MOVES OUT ACROSS THE AREA AND INTERACTS WITH THE SURFACE WARM
FRONT DRAPED ACROSS THE AREA. IN ALL...THIS IS A RATHER DAMP
FORECAST.
TODAY HAVE USED MCS TECHNIQUES AND MODELS AS WELL AS NOWCASTING
TECHNIQUES INDICATE THIS MCS WILL MOVE OUT OF THE EASTERN PORTIONS
OF THE FORECAST AREA ABOUT 15Z. UNTIL THEN THOUGH...AM CARRYING
SOME VERY HIGH POPS FOR ABOUT THE SOUTHERN THREE QUARTERS OF THE
AREA. DO NOT EXPECT MUCH ADDITIONAL THUNDER DEVELOPMENT AS WE ARE
GETTING INTO THE TIME RANGE WHEN THE LOW LEVEL JET SHOULD START TO
WEAKEN. THERE MAY BE SOME LINGERING SHOWERS PAST 15Z...BUT HAVE
KEPT POPS PRETTY LOW FOR NOW.
THEN...WE SHOULD MANAGE TO BREAK OUT INTO AT LEAST A LITTLE
SUNSHINE AS THE CLOUDS WITH THE MCS ARE SWEPT EAST. THIS SHOULD
ALLOW TEMPERATURES TO RISE INTO THE 60S AND EVEN LOW TO MID
70S...MAINLY SOUTHWEST WHERE THE SUNSHINE BREAKS OUT SOONEST. THE
WARM FRONT WILL BE DRAPED FROM EAST TO WEST ACROSS THE FORECAST
AREA OVER ABOUT THE NORTHERN THIRD OF THE AREA BY AFTERNOON...AND
THE WARM AIR THAT SURGES INTO THE AREA ON THE SOUTH SIDE OF THE
BOUNDARY SHOULD HELP BOOST TEMPS AS WELL. THE MCS WILL HAVE LEFT
BEHIND AN OUTFLOW BOUNDARY WHICH MAY SERVE AS A FOCUS FOR
ADDITIONAL THUNDERSTORM DEVELOPMENT THIS AFTERNOON...AND AM
CARRYING SOME LOW CHANCE POPS FOR THEN.
TONIGHT THE NEXT SURGE OF WAA AND THETA-E ADVECTION SHOULD CAUSE
THUNDERSTORMS TO BEGIN DEVELOPING OVER THE AREA DURING THE
EVENING...AND GRADUALLY INCREASING IN COVERAGE OVERNIGHT. AS THERE
ARE NOT ANY INITIAL STRONG FEATURES TO PIN DOWN AND TIMING IS
SOMEWHAT PROBLEMATIC...HAVE PLACED HIGHEST POPS ALONG THE WARM
FRONT AND GONE SLIGHTLY LOWER TOWARDS THE SOUTH. THIS WILL NEED
SOME REFINEMENT AS FEATURES SET UP LATER TODAY. MIN TEMPS SHOULD
BE KEPT MILD BY THE WARM AIRMASS AND AT LEAST BROKEN CLOUD COVER.
MIN TEMPS ONLY EXPECTED TO FALL INTO THE 50S.
LE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 330 AM CDT MON APR 8 2013
FORECAST FOCUS ON MAJOR SLOW MOVING STORM SYSTEM THIS WEEK THEN
COLDER TEMPERATURES BEHIND THE SYSTEM. FORECAST BASED ON THE MORE
CONSISTENT ECMWF MODEL...THE GFS SEEMS A BIT TOO AGGRESSIVE WITH
MOVING THE DEEP TROUGH TO THE EAST TOO QUICKLY.
TUESDAY THROUGH WEDNESDAY...SEVERAL ROUNDS OF WIDESPREAD SHOWERS AND
THUNDERSTORMS AS DEEP WESTERN TROUGH PUSHES SLOWLY ACROSS THE
MIDWEST. FRONTAL BOUNDARY WILL BE LOCATED IN THE CWA ALONG WITH
CONTINUED EXCELLENT FEED OFF THE GULF. PRECIPITABLE WATER WILL BE
WELL OVER AN INCH WITH THE POTENTIAL FOR HEAVY RAIN AMOUNTS OF AT
LEAST 1 TO 3 INCHES DURING THIS TIME FRAME ESPECIALLY IF REPEATED
BOUTS OF THUNDERSTORMS TRAIN OVER THE SAME AREAS. WARM ON TUESDAY
WITH HIGHS IN THE 70S ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80.
WEDNESDAY IS THE DAY WHEN THE MAIN TROUGH/DYNAMICS ARRIVE WITH THE
HEAVIEST RAINS AND POSSIBLE SEVERE WEATHER. HOWEVER THIS WILL DEPEND
ON EXACT TRACK OF THE SURFACE LOW...TIMING OF THE STRONG COLD FRONT
AND AMOUNT OF INSTABILITY. AT THIS POINT SPC HAS A SLIGHT RISK FOR
SEVERE IN OUR SOUTHERN COUNTIES TUESDAY AND TUESDAY NIGHT WITH THE
MAIN THREAT OF SEVERE ON WEDNESDAY MAINLY EAST/SOUTH OF THE DVN
CWA.
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...COLDER AIR WILL BE FILTERING
INTO THE REGION AS THE DEEP TROUGH PUSHES EASTWARD. LOOKS COLD
ENOUGH FOR EITHER A RAIN/SNOW MIX OR ALL SNOW BUT MUCH OF THE
AVAILABLE MOISTURE WILL HAVE PUSHED EAST OF THE CWA BY THE TIME THE
COLD AIR ARRIVES. THEREFORE NOT EXPECTING ANY ACCUMULATION. LOOKS
DRY ON FRIDAY. HOWEVER...TEMPERATURES WILL BE BELOW NORMAL WITH
HIGHS MAINLY IN THE 40S WITH LOWS DIPPING INTO THE 20S AT SOME
LOCATIONS.
THIS WEEKEND/WEEK 2...THE 00Z ECMWF HAS BACKED OFF ON RAIN ARRIVING
LATER THIS WEEKEND AND NOW INDICATES DRY WEATHER ALONG WITH WARMING
TEMPERATURES. THIS AHEAD OF ANOTHER MAJOR TROUGH DIGGING INTO THE
WESTERN STATES. THIS FITS THE TELECONNECTIONS WITH THE AO/NAO GOING
NEUTRAL TO POSITIVE AND THE PNA GOING NEGATIVE. THIS FAVORS AN
ACTIVE STORM TRACK IN THE MIDDLE OF THE COUNTRY WITH DEEP TROUGHING
IN THE WEST AND RIDGING IN THE EAST. IF THE ECMWF IS CORRECT THEN IT
WILL BE DRY UNTIL NEXT TUESDAY WHEN A VIGOROUS NEGATIVE TILT TROUGH
AND DEEPENING SURFACE LOW ARRIVES FOLLOWED BY COOLER TEMPERATURES
AGAIN.
HAASE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM CDT MON APR 8 2013
VFR WX WILL BE SEEN THROUGH 00Z/09 AT KCID/KMLI/KBRL. IFR
CONDITIONS AT KDBQ SHOULD GRADUALLY IMPROVE TO MVFR. AFT 00Z/09
ANOTHER THUNDERSTORM COMPLEX WILL DEVELOP ACROSS NORTHERN MISSOURI
AND THEN MOVE NORTH. ALL TAF SITES WILL BE IMPACTED WITH MVFR IF
NOT IFR CONDITIONS WITH PROBABLE TSRA. THE POTENTIAL DOES EXIST
FOR LIFR CONDITIONS BY SUNRISE TUESDAY. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...HAASE
AVIATION...08
AREA FORECAST DISCUSSION
NWS TOPEKA KS
326 PM CDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
19Z WATER VAPOR IMAGERY SHOWS AN UPPER LOW DIGGING SOUTHEAST INTO
SOUTHERN NV AND AZ. AT THE SURFACE A WEAK BOUNDARY NOTED MORE IN THE
DEWPOINT FIELD HAS LIFTED INTO SOUTHERN NEB.
TONIGHT WITH THE UPPER LOW ACROSS THE SOUTHWEST...THE FORECAST AREA
SHOULD REMAIN MAINLY UNDER SHORTWAVE RIDGING ALOFT WITH SOUTHERLY
RETURN FLOW PERSISTING. THIS LOW LEVEL FLOW IS EXPECTED TO ADVECT AN
ELEVATED MIXED LAYER OR CAPPING INVERSION NORTH INTO NEB AND THE
LATEST RAP SOUNDINGS SUPPORT THIS IDEA WITH A STRENGTHENING
INVERSION EARLY THIS EVENING ALONG THE NEB STATE LINE. SO AM
THINKING THAT ELEVATED STORMS ARE MORE LIKELY TO OCCUR OVER SOUTHERN
NEB WHERE ISENTROPIC UPGLIDE INTERACTS WITH THE WEAK BOUNDARY. SOME
OF THE LATEST HI RES MODELS ARE SHOWING A SIMILAR IDEA. STORMS THAT
FORM IN NORTH KS MAY STILL HAVE THE POTENTIAL FOR LARGE HAIL GIVEN
STEEP MID LEVEL LAPSE RATES. WITH CONTINUED SOUTHERLY FLOW AND
MOISTURE ADVECTION INTO THE AREA...A STRATUS DECK IS EXPECTED TO
REDEVELOP THIS EVENING. THE CLOUD COVER COMBINED WITH A WARM MOIST
BOUNDARY LAYER SHOULD CREATE A VERY MILD NIGHT WITH LOWS ONLY IN THE
LOWER 60S.
BY TUESDAY...THE MODELS HAVE TRENDED A LITTLE SLOWER WITH THE
FRONTAL PASSAGE AND ONLY BEGIN TO BRING IT INTO THE NORTH CENTRAL
COUNTIES BY LATE AFTERNOON. WITH THE SUBSTANTIAL CAPPING INVERSION
IN THE WARM SECTOR...THINK THAT DEEP MOIST CONVECTION WILL LIKELY
HOLD OFF UNTIL THE FRONT MOVES THROUGH TO LIFT SURFACE PARCELS TO
THE LFC. WITH THE LINEAR FORCING FOR CONVECTION...THUNDERSTORMS MAY
QUICKLY DEVELOP INTO A SQUALL LINE WITH STRONG WINDS AND HAIL THE
MOST LIKELY HAZARD. SO THE FORECAST SHOWS POPS INCREASING LATE IN
THE AFTERNOON ACROSS NORTH CENTRAL KS. SINCE THERE IS NO REAL COLD
AIR ADVECTION TO SPEAK OF THROUGH THE DAY...HIGHS SHOULD AGAIN BE
MILD WITH UPPER 60S TO 70S FROM NORTH CENTRAL KS TO EAST CENTRAL KS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
FOR THE MOST PART THE MAIN SQUALL LINE APPEARS POISED TO MOVE
ACROSS THE FORECAST AREA BETWEEN 00Z AND 06Z DURING THE EVENING
HOURS ON TUESDAY. WARM NOSE AROUND 775MB WILL INHIBIT CONVECTION
IN THE WARM SECTOR AND THINK MOST LOCATIONS WILL NOT SEE ACTIVITY
UNTIL THE FORCING WITH THE FRONT BREAKS THROUGH. MAY HAVE ONGOING
CONVECTION ALONG AND NORTH OF THE WARM FRONT ACROSS NORTHERN
KANSAS AT THE BEGINNING OF THE PERIOD AS WELL. 0-6KM WIND SHEAR
VECTORS GENERALLY 50-60KTS BUT DIRECTIONAL TURNING IS NOT AS
IMPRESSIVE. GIVEN INSTABILITY GENERALLY 800-1200J/KG THINK THAT
MAIN CONCERN WILL BE WINDS WITH THE STORMS AS THE LINE PASSES.
SOME LOCALLY HEAVY RAIN ALSO POSSIBLE AND CANNOT RULE OUT ISOLATED
TORNADOES ALONG THE LINE...BUT AT THIS TIME IS NOT THE PRIMARY
CONCERN. TRAILING RAIN AND ISOLATED T CONTINUE THROUGH THE NIGHT.
NEXT CONCERN IS COLD AIR DIVING SOUTHWARD BEHIND THIS SYSTEM. WARM
NOSE IS INITIALLY SO WARM THINK THAT PRECIP WILL STAY AS RAIN
DESPITE COOLING SURFACE TEMPERATURES...BUT AS THIS NOSE COOLS
THEN MORE COMPLEX PRECIP TYPES COME INTO PLAY. BY THE TIME IT GETS
COLD ENOUGH ALOFT FOR SNOW...THE MOISTURE AND LIFT ARE GENERALLY
EAST OF THE AREA. AS THE COLD AIR AT THE SURFACE GETS COLDER...THE
CHANCE FOR A CHANGEOVER TO SLEET OR FREEZING RAIN ALSO INCREASES.
HAVE STARTED WITH A RAIN SNOW MIX ACROSS THE NORTHWEST...BUT THINK
THIS WILL BE MORE OF A MIXED BAG...WITH LITTLE OF IT STICKING TO
THE GROUND AND ANY ACCUMULATION ON ELEVATED SURFACES. INITIAL
CHANCES FOR MIXED PRECIP ARE NORTH AND WEST OF MANHATTAN AFTER
MIDNIGHT INTO WEDNESDAY MORNING...RETREATING SOMEWHAT BACK INTO
NORTH CENTRAL KANSAS WEDNESDAY AFTERNOON. THE CHANCES THEN SPREAD
EASTWARD WITH A MIX POSSIBLE WEDNESDAY NIGHT INTO THURSDAY MORNING
ACROSS MUCH OF NORTHEAST AND EAST CENTRAL KANSAS. WILL HAVE TO
MONITOR FORECAST SOUNDINGS OVER NEXT FEW RUNS...BUT A QUICK ROUND
OF SOME TYPE OF FREEZING PRECIP LOOKS POSSIBLE FOR NORTH CENTRAL
KANSAS.
THE AIRMASS THAT DROPS INTO THE PLAINS BEHIND THE FRONT HOLDS
HIGHS IN THE 30S AND 40S WEDNESDAY...40S FOR THURSDAY...SLOWLY
RISING TOWARD 50 ON FRIDAY AND BACK TOWARD NORMAL LATER IN THE
WEEKEND. OVERNIGHT LOW TEMPERATURES MAY FALL BELOW FREEZING
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...FINALLY RISING BACK INTO
THE 40S SATURDAY NIGHT. ALTHOUGH THE GROWING SEASON IS SLOW TO
START...ITS WORTH NOTING THAT EARLY EMERGENT VEGETATION WILL SEE
COLD OVERNIGHT LOWS MID TO LATE WEEK. 67
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1226 PM CDT MON APR 8 2013
THE TERMINALS SHOULD REMAIN WITHIN THE WARM MOIST SECTOR THROUGH
18Z WED WITH THE MODELS SHOWING AN EML EVENTUALLY ADVECTING OVER
THE AREA CAPPING THE BOUNDARY LAYER. SOME OF THE HIGH RES MODELS
SUGGEST THERE COULD BE SOME ISOLATED CONVECTION THIS AFTERNOON.
THINK THIS ACTIVITY IS MORE LIKELY TO THE NORTH OF THE TERMINALS
SO WILL NOT INCLUDE A MENTION. CIGS SHOULD IMPROVE ABOVE 3 KFT
THIS AFTERNOON ONLY TO COME BACK DOWN BELOW 2 KFT OVERNIGHT. MOS
GUIDANCE IS AGAIN HITTING IFR CIGS. CONFIDENCE IS MARGINAL THAT
IFR CIGS WILL MOVE IN...SO HAVE KEPT CIGS JUST ABOVE 1 KFT FOR
NOW.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS WICHITA KS
324 PM CDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 322 PM CDT MON APR 8 2013
THE MAIN FORECAST CONCERNS ARE THE SEVERE WEATHER CHANCES TONIGHT
AND TOMORROW AND WINTRY PRECIPITATION BEHIND THE COLD FRONT TUESDAY
NIGHT/WEDNESDAY.
A LARGE POTENT UPPER TROUGH IS DIGGING INTO THE INTERIOR MOUNTAIN
WEST THIS AFTERNOON WITH A WEAK WAVE MOVING NORTHEAST OVER THE GREAT
LAKES. THE DEEP TROUGH WILL BE THE WEATHER MAKER FOR THE NEXT FEW
DAYS. MOSTLY CLOUDY SKIES COVER MUCH OF KANSAS EXCEPT EXTREME
WESTERN AND SOUTHWESTERN SECTIONS. TEMPERATURES ARE WARM...IN THE
LOW 70S AND WINDS ARE BREEZY BETWEEN 10 AND 20 MPH.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
THIS PERIOD IS THE ONE TO WATCH IN TERMS OF SEVERE WEATHER CHANCES.
THE POTENT UPPER LEVEL DISTURBANCE IS SLOWLY MAKING ITS WAY EASTWARD
WITH WEAK DIFFLUENCE OVER THE CENTRAL PLAINS. SOUTHERN KANSAS IS IN
THE WARM SECTOR AND LOW LEVEL INHIBITION (CIN) IS HIGH. THE RUC AND
NAM DO SHOW AN AREA OVER EXTREME NORTH CENTRAL OKLAHOMA WHERE CIN
DECREASES LATE THIS AFTERNOON/EARLY EVENING WHERE A THUNDERSTORM
COULD DEVELOP. CONFIDENCE IS NOT OVERLY HIGH THAT MUCH OF SOUTH
CENTRAL KANSAS WILL SEE A STORM...BUT AREAS WEST OF HIGHWAY 14 COULD
SEE A THUNDERSTORM BEFORE DARK THIS EVENING.
BEYOND THIS TONIGHT...THE MAIN FOCUS WILL BE OVER THE HIGH
PLAINS AND CENTRAL KANSAS NORTH OF I-70 WHERE CIN WILL BE ABLE TO
ERODE QUICKER BEFORE THE NOCTURNAL BOUNDARY LAYER TAKES HOLD. THESE
STORMS HAVE THE CHANCE OF BEING SEVERE WITH MODEST 1000-1500 J/KG
CAPE AND 40-55 KTS 0-6KM BULK SHEAR. THIS AREA WILL TRANSLATE
EASTWARD AND MOVE INTO CENTRAL KANSAS. THE BEST CHANCES FOR
PRECIPITATION OVERNIGHT WILL BE ALONG AND NORTH OF I-70.
THINGS CHANGE TUESDAY WITH THE VERY STRONG COLD FRONT BEGINNING TO
GAIN ITS MOMENTUM TUESDAY MORNING AS THE UPPER TROUGH MOVES INTO THE
AREA. THE POTENT FRONT WILL APPROACH CENTRAL KANSAS BY AFTERNOON.
AS THE FRONT REACHES CENTRAL AND EASTERN KANSAS...IT WILL BE ABLE TO
TAP MOIST BOUNDARY LAYER AIR...AND THE CAP WILL ERODE ALONG AND
NEAR THE FRONT IN THE AFTERNOON HOURS. A FEW DISCRETE STORMS MAY BE
ABLE TO DEVELOP EARLY...BUT WITH THE LARGE AMOUNT OF LINEAR FORCING
WITH THE FRONT A SQUALL LINE IS EXPECTED TO BECOME THE MAIN
CONVECTIVE MODE. THE STORMS ARE EXPECTED TO FIRE NEAR THE
I-135/I-35 CORRIDOR AND MOVE EASTWARD FROM THERE DURING THE EVENING
AND OVERNIGHT HOURS. THE MAIN THREATS ARE LARGE HAIL AND DAMAGING
WINDS WITH THE LINEAR CONVECTIVE MODE...BUT CANNOT RULE OUT A
TORNADO EARLY.
OUTSIDE OF THE SEVERE THUNDERSTORM CHANCES...THE OTHER MAIN CONCERN
IS TEMPERATURES BEHIND THE FRONT. THIS FRONT IS BEING FORCED SOUTH
BY COLD ARCTIC AIR. THIS WILL CAUSE TEMPERATURES TO DROP
DRASTICALLY ONCE THE FRONT MOVES THROUGH. USED THE NAM...FEELING IT
HAS THE BEST RESOLUTION AS A NON-DIURNAL TREND OVERNIGHT TONIGHT
THROUGH TOMORROW NIGHT.
BILLINGS
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
TUESDAY NIGHT - WEDNESDAY:
COLD TEMPERATURES BEHIND THE FRONT WILL BRING A SHOCK TO OUR
SYSTEMS...AS PRECIPITATION ON THE BACK SIDE OF THE UPPER LOW COULD
FALL AS A WINTRY MIX TUESDAY NIGHT AND EARLY WEDNESDAY IN CENTRAL
KANSAS. CONFIDENCE IN PRECIP TYPE IS LOW GIVEN LOW LEVEL PROFILES.
WILL ALLOW NEXT COUPLE SHIFTS TO FINE TUNE THESE CHANCES. BY
WEDNESDAY DAYTIME HIGH TEMPERATURES WILL BE WELL BELOW NORMAL...IN
THE UPPER 30S AND LOW 40S.
THURSDAY - SATURDAY:
BY THURSDAY THINGS DRY OUT WITH THE UPPER WAVE MAKING ITS WAY OVER
THE PLAINS...WITH SUBSIDENCE AND SURFACE HIGH PRESSURE BUILDING IN
BEHIND THE FRONT. THE ARCTIC AIR WILL HOLD ON AND TEMPS WILL
STRUGGLE TO WARM INTO THE 50S ON THURSDAY AND FRIDAY. BY SATURDAY
HIGH PRESSURE WILL MOVE SOUTHEAST AND SOUTHERLY FLOW WILL RETURN
HELPING TEMPERATURES TO IMPROVE BACK TO NEAR NORMAL IN THE LOW 60S.
SUNDAY - MONDAY:
ANOTHER WAVE WILL IMPACT THE REGION LATE IN THE WEEKEND AND EARLY
NEXT WEEK...BUT THE GUIDANCE IS OUT OF PHASE WITH THE SOLUTIONS.
THE GFS IS PULLING A FRONT THROUGH MUCH QUICKER THAN THE ECMWF.
CONFIDENCE ON THIS FEATURE IS LOW AND WENT WITH MODEL CONSENSUS.
BILLINGS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1237 PM CDT MON APR 8 2013
STRATOCU AND STRATUS CIGS WILL CONTINUE TO PLAGUE THE ENTIRE AREA
THROUGH THE FORECAST VALID PERIOD...WITH PRIMARILY MVFR DURING THE
AFTERNOON AND EARLY EVENING LOWERING TO IFR CIGS/VSBYS TONIGHT
INTO TUESDAY MORNING. CONVECTION IS EXPECTED TO DEVELOP ACROSS THE
HIGH PLAINS LATE THIS AFTERNOON AND EARLY EVENING...WHICH COULD
MOVE INTO PORTIONS OF CENTRAL KANSAS OVERNIGHT. A STRONG COLD
FRONT WILL IMPACT THE AREA JUST BEYOND THE FORECAST VALID PERIOD
WITH STRONG TO SEVERE CONVECTION EXPECTED TO AFFECT THE AREA ON
TUESDAY AFTERNOON AND EVENING.
KED
&&
.FIRE WEATHER...
ISSUED AT 322 PM CDT MON APR 8 2013
FIRE WEATHER CONCERNS ARE LOW DURING THE NEXT COUPLE OF DAYS ARE
LOW...BUT BY WEDNESDAY STRONG WINDS BEHIND THE COLD FRONT WILL CAUSE
GRASSLAND FIRE DANGER TO BE VERY HIGH ACROSS MUCH OF CENTRAL AND
SOUTH CENTRAL KANSAS.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 64 72 34 43 / 20 60 60 40
HUTCHINSON 63 72 29 41 / 20 60 40 30
NEWTON 63 69 30 39 / 20 60 60 40
ELDORADO 63 73 35 43 / 10 60 60 40
WINFIELD-KWLD 64 74 36 44 / 10 60 60 40
RUSSELL 60 65 22 38 / 40 50 40 10
GREAT BEND 61 67 24 39 / 30 50 40 10
SALINA 63 70 31 41 / 30 60 50 30
MCPHERSON 63 69 30 40 / 20 60 50 30
COFFEYVILLE 64 75 45 46 / 10 40 70 50
CHANUTE 63 73 44 45 / 10 50 70 50
IOLA 63 73 44 45 / 10 50 70 50
PARSONS-KPPF 64 75 44 45 / 10 50 70 50
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1226 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1028 AM CDT MON APR 8 2013
12Z UPPER AIR ANALYSIS INDICATED THE EML HAS YET TO ADVECT INTO
NORTHEAST KS WITH THE WARMER 700 MB TEMPS STILL ACROSS OK. THE RAP
AND NAM INDICATE THE WARM AIR ADVECTION PATTERN AND WEAK
ISENTROPIC LIFT WILL PERSIST THROUGH THE DAY. WITH THE CAP NOT AS
STRONG AS EARLIER ANTICIPATED...HAVE PUT A SLIGHT CHANCE FOR
SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST FOR THIS
AFTERNOON ACROSS NORTH CENTRAL AND NORTHEAST KS THINKING THERE
COULD BE SOME POPCORN CONVECTION ON THE NORTHERN EDGE OF THE EML.
THE RAP AND HRRR ARE SHOWING THIS POTENTIAL AND AGITATED CU FIELD
ACROSS CENTRAL KS SHOWS THERE IS SOME ELEVATED INSTABILITY TO WORK
WITH.
UPDATE ISSUED AT 642 AM CDT MON APR 8 2013
WEAK ISENTROPIC LIFT MAY CAUSE A FEW ISOLATED SHOWERS ALONG THE
WESTERN AND SOUTHERN COUNTIES OF THE CWA THIS MORNING. ONCE THE
BOUNDARY LAYER MIXES ABOVE 925MB THESE WEAK RAIN SHOWERS SHOULD
DISSIPATE AROUND 10 AM. PATCHY GROUND FOG WAS DEVELOPING AROUND
THE CWA...SO I HAVE INCLUDED PATCHY FOG IN THE FORECAST THROUGH 10
AM.
UPDATED THE AVIATION DISCUSSION AS WELL.
GARGAN
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT MON APR 8 2013
TODAY...AN INTENSE UPPER LEVEL TROUGH WILL DIG SOUTHEAST FROM OR AND
NORTHERN CA INTO NV AND NORTHERN AZ BY LATE THIS AFTERNOON. A LEE
SURFACE LOW WILL DEEPEN OVER SOUTHEAST CO...CAUSING SURFACE AND
850MB WINDS TO BACK TO THE SOUTHEAST ACROSS MUCH OF KS. THE STRONGER
WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL KS DURING THE
AFTERNOON HOURS WITH WINDS INCREASING TO NEAR 30 MPH WITH GUSTS TO
40 MPH. WINDS ACROSS THE CWA WILL INCREASE TO 15 TO 25 MPH WITH
GUSTS OF 30 MPH ACROSS NORTH CENTRAL KS DURING THE AFTERNOON HOURS.
A SURFACE DRYLINE WILL PUNCH NORTHEAST INTO EXTREME SOUTHWEST KS
DURING THE AFTERNOON HOURS AND THEN ARC NORTHWEST INTO NORTHEAST CO.
SURFACE CONVERGENCE AHEAD OF THE DRYLINE...ALONG WITH ASCENT AHEAD
OF THE H5 TROUGH MOVING INTO NORTHERN AZ...WILL CAUSE THUNDERSTORMS
TO DEVELOP DURING THE AFTERNOON HOURS ACROSS WESTERN KS AND
NORTHEAST CO. VERTICAL WIND SHEAR PROFILES AND SUFFICIENT
INSTABILITY WILL ALLOW FOR SOME SEVERE THUNDERSTORMS TO DEVELOP
ACROSS WESTERN KS AND NORTHEAST CO. THOUGH...IF THE CLOUD COVER
HOLDS THROUGH THE DAY ACROSS WESTERN KS THEN THE INSTABILITY MAY NOT
BE SUFFICIENT FOR SEVERE THUNDERSTORMS. A COMPLEX OF STRONG TO
SEVERE STORMS MAY MOVE INTO NORTH CENTRAL KS TONIGHT.
ACROSS EASTERN KS...A COMBINATION OF BOTH THE DOWN STREAM H5 RIDGE
AMPLIFYING AND AN EML SPREADING NORTHEAST ACROSS THE CWA WILL CREATE
A STRONG CAPPING INVERSION. THE CAPPING INVERSION SHOULD PREVENT ANY
SURFACE BASED THUNDERSTORMS FROM DEVELOPING. THERE MAY
BE SOME ISOLATED SHOWERS SOUTH OF I-70 DURING THE DAY DUE TO THE
INCREASING DEEP MOISTURE ADVECTION...BUT AT THIS TIME THE MOIST
PARCELS SHOULD NOT BE FORCED TO THEIR LEVEL OF FREE CONVECTION
ABOVE THE CAPPING INVERSION. THEREFORE...I ONLY WENT WITH 14 POPS
DURING THE DAY.
THE STRATUS CLOUD COVER MAY HOLD IN FOR MOST OF THE DAY BUT IF THERE
ARE SOME BREAKS IN THE CLOUD COVER THIS AFTERNOON HIGH TEMPERATURES
MAY REACH THE MID 70S...BUT IN AREAS WHERE THE CLOUD COVER HOLDS
HIGHS MAY ONLY REACH AROUND 70 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 344 AM CDT MON APR 8 2013
TONIGHT...THE BEST CHANCES FOR THUNDERSTORMS TONIGHT WILL BE ACROSS
THE NORTHERN CWA FROM LATER THIS EVENING THROUGH THE OVERNIGHT HOURS
AS CONVECTION THAT DEVELOPS IN THE HIGH PLAINS/NORTHWEST KS
SPREADS/DEVELOPS EASTWARD...ALTHOUGH THE OVERALL AREA OF CONVECTION
APPEARS WILL BE EVEN FURTHER NORTH AND WEST THAN PREVIOUS TRENDS
WITH FORECAST INHIBITION EVEN MORE PRONOUNCED SOUTH AND EAST. HAVE
THEREFORE LOWERED POPS ACROSS THE EAST CENTRAL NOT ONLY FOR TONIGHT
BUT ALSO FOR TUESDAY MORNING AS HIGHER QPF REMAINS WELL NORTH AND
WEST CLOSER TO THE FRONT.
AS THE PRIMARY SHORTWAVE TROUGH ROTATES OUT OF THE ROCKIES AND INTO
THE NORTHERN HIGH PLAINS...THE COLD FRONT WILL SURGE EASTWARD
THROUGH THE DAY...MOVING THROUGH MUCH OF THE NORTH CENTRAL COUNTIES
IN THE MORNING AND TO NEAR THE TURNPIKE BY LATE AFTERNOON BEFORE
CLEARING THE REMAINDER OF THE EASTERN COUNTIES THROUGH THE EVENING.
MUCH OF THE EARLY DAY CONVECTION WILL LIKELY OCCUR ALONG AND JUST
BEHIND THE FRONT BEFORE SHIFTING SOUTH AND EAST WITH THE FRONT INTO
THE EVENING HOURS OVER THE EAST CENTRAL COUNTIES AS LARGE SCALE
ASCENT SPREADS NORTH AND EASTWARD ALONG AND JUST BEHIND THE FRONT
LATER IN THE AFTERNOON AND EVENING. ALTHOUGH SHEAR WILL REMAIN
STRONG AHEAD OF FRONT...THE STRONG CAPPING INVERSION WILL ALSO
REMAIN IN PLACE. WHEN COMBINED WITH THE FASTER FROPA...CLOUD COVER
AND EXTENSIVE PRECIP...THE OVERALL INSTABILITY AND SEVERE WEATHER
POTENTIAL IS HARDER TO PINPOINT. ALTHOUGH STRONG CONVECTION WILL BE
POSSIBLE ALONG THE FRONT THROUGH THE DAY...THE MOST ACTIVE PERIOD
APPEARS WILL SETUP ACROSS NORTHEAST AND EAST CENTRAL KS IN THE
MID/LATE AFTERNOON AS THE FRONT PUSHES THROUGH AS THE MAIN SHORTWAVE
TROUGH LIFTS OUT INTO THE PLAINS. SCATTERED STRONG TO SEVERE
THUNDERSTORMS MAY FORM A SQUALL LINE INTO THE EVENING AS IT PUSHES
EASTWARD. THIS SHOULD ALSO BE THE TIME OF THE HEAVIER PRECIP ACROSS
THE SOUTHEAST COUNTIES. AS COLDER AIR WORKS SOUTH AND EAST INTO THE
CWA LATE TUESDAY NIGHT AND INTO WED...A RAIN/SNOW MIX IS POSSIBLE
ACROSS THE WESTERN 1/3 OF THE CWA...THEN POSSIBLY OVER THE REMAINDER
OF THE NORTH/NORTHEAST CORNER WEDNESDAY NIGHT/EARLY THU MORNING. AT
THIS TIME...ONLY LIGHT SNOWFALL AMOUNTS...IF ANY...ARE EXPECTED
ACROSS THE FAR NORTHWEST COUNTIES. HOWEVER...IF THE SYSTEM OR DRY
SLOT MOVES OUT FURTHER SOUTH AND EAST THAN FORECAST...MORE IN THE
WAY OF ACCUMULATING SNOW WOULD BE POSSIBLE IN THE NORTH CENTRAL AND
BORDER COUNTIES ALONG THE NORTHERN BORDER.
EITHER WAY...IT SHOULD BE DRY ACROSS THE CWA BY THU AFTERNOON INTO
FRIDAY BEFORE ANOTHER CHANCE FOR SHOWERS RETURNS TO THE AREA OVER
THE WEEKEND AS WARM AIR ADVECTION INCREASES AHEAD OF ANOTHER
SHORTWAVE TROUGH. HIGHS IN THE 40S ON THURSDAY SHOULD WARM BACK INTO
THE 60S AND 70S FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1226 PM CDT MON APR 8 2013
THE TERMINALS SHOULD REMAIN WITHIN THE WARM MOIST SECTOR THROUGH
18Z WED WITH THE MODELS SHOWING AN EML EVENTUALLY ADVECTING OVER
THE AREA CAPPING THE BOUNDARY LAYER. SOME OF THE HIGH RES MODELS
SUGGEST THERE COULD BE SOME ISOLATED CONVECTION THIS AFTERNOON.
THINK THIS ACTIVITY IS MORE LIKELY TO THE NORTH OF THE TERMINALS
SO WILL NOT INCLUDE A MENTION. CIGS SHOULD IMPROVE ABOVE 3 KFT
THIS AFTERNOON ONLY TO COME BACK DOWN BELOW 2 KFT OVERNIGHT. MOS
GUIDANCE IS AGAIN HITTING IFR CIGS. CONFIDENCE IS MARGINAL THAT
IFR CIGS WILL MOVE IN...SO HAVE KEPT CIGS JUST ABOVE 1 KFT FOR
NOW.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WOLTERS
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS GRAY ME
704 PM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES REGION TONIGHT
THEN MOVE QUICKLY ACROSS NORTHERN NEW ENGLAND AND THROUGH THE GULF
OF MAINE ON TUESDAY. THIS WILL GIVE US A PERIOD OF RAIN LATE
TONIGHT INTO TUESDAY WITH SNOW POSSIBLE OVER MORE NORTHERN AREAS.
THE LOW WILL MOVE QUICKLY OUT TO SEA TUESDAY EVENING AS FAIR
WEATHER SETTLES IN BRIEFLY. A FRONTAL SYSTEM SETS UP OVER THE
REGION AS LOW PRESSURE HEADS EAST ALONG IT TUESDAY NIGHT BRINGING
A CHANCE OF MORE RAIN LATE TUESDAY NIGHT. THE WEST TO EAST FRONT
DRAPED ACROSS THE REGION THEN PROVIDES CLOUDS AND UNSETTLED
WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST ALONG
THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF PRECIPITATION
ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING CLOUDS AND A FEW
MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY SATURDAY. HIGH PRESSURE
WILL BUILD EAST FROM THE GREAT LAKES FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...
SEA BREEZES KNOCKED TEMPS DOWN ALONG THE COAST DURING THE LAST 2
HOURS. NEVERTHELESS...NW BREEZES ALLOWED PORTLAND TO TOP OUT AT THEIR HIGHEST
TEMPERATURE OF THE YEAR...REACHING 61 DEGREES. TO ACCOMPLISH THIS
FEET...WE HAD TO MOVE HIGHER THAN THE 59 DEGREES...SET BACK ON
JANUARY 14TH!
LATEST RUC SHOWS PCPN REACHING WRN PTNS OF OUR FORECAST AREA
SHORTLY AFTER MIDNIGHT. IN THE MEANTIME...CLOUDS WILL OVERSPREAD
THE REGION THIS EVENING FROM WEST TO EAST.
MADE MINOR ADJUSTMENTS TO THE DEW POINT AND WIND FIELDS.
OTRW...LITTLE IN THE WAY OF CHANGES TO THE GRIDS.
PREV DISC...
SFC HIGH MOVES QUICKLY OUT TO SEA THIS EVE AS LOW PRES
MOVES E FROM THE GREAT LAKES REGION TNGT. THE LOW IS ASSOCIATED
WITH AN UPR LVL TROF THAT IS MOVING QUICKLY E THRU THE STRONG
WESTERLIES ALOFT. THE LOW WILL SPREAD CLOUDS THEN RA E INTO THE
FCST AREA OVERNIGHT. TEMP PROFILE MAY BE COLD ENOUGH FOR -SN OR
-RASN OVER OUR MORE NRN ZONES IN ME...IN PARTICULAR NRN FRANKLIN
AND CENTRAL SOMERSET COUNTIES AS WELL AS THE HIGHEST TERRAIN IN
THE WHITE MTS OF NRN NH. HOWEVER...ANY ACCUMULATION WILL BE LGT IF
ANY AT ALL.
TEMPS WILL STAY MILD RANGING FROM THE MID 30S N TO THE LOWER 40S S
EXCEPT FOR SOME LOWER 30S ACROSS FAR NRN ZONES WHERE THE -SN IS
PSBL. LGT WINDS WILL TURN TO AN EASTERLY DIRECTION AHEAD OF THE
APPROACHING LOW.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE NEAR TERM
FCST.
&&
.SHORT TERM /TUESDAY NIGHT/...
THE UPR LVL SHORT WAVE TROF MOVES QUICKLY TO THE E AS THE UPR LVL
FLOW CONTINUES VERY STRONG ON TUESDAY. THIS BRINGS THE SFC LOW
ACROSS NRN NEW ENGLAND TUESDAY MORNING AND THRU THE GULF OF MAINE
TUESDAY AFTERNOON. THIS WILL CONT RA...OR SN/MIXED RASN FAR NRN
ZONES INTO TUESDAY WITH DRIER WX AND SOME CLEARING TO FOLLOW
TUESDAY AFTERNOON OVER NH AND FROM MID TO LATE AFTERNOON OVER ME.
FAIR WX TUESDAY EVE IN THE WAKE OF THE LOW. HOWEVER...A FNT SETS
UP OVER THE REGION WITH WEAK LOW PRES APPROACHING FROM THE W. THIS
WILL BRING MORE CLOUDS BACK IN WITH A CHC OF RA LATE TUESDAY NGT.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE SHORT TERM
FCST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WE BEGIN THE PERIOD WITH A FLAT RIDGE TO OUR SOUTH AND AN UPPER
VORTEX OVER EASTERN CANADA WITH FORECAST AREA JUST TO THE SOUTH OF
THE MEAN JET AXIS. UPSTREAM...AN UPPER TROUGH WILL BE SITUATED
JUST TO THE LEE OF THE ROCKIES. THAT UPPER TROUGH LIFTS OUT INTO
THE GREAT LAKES BY LATE IN THE WORKWEEK WHEN FORECAST CONFIDENCE
DIMINISHES IN INCREASING MODEL SPREAD. IN THE DAILIES...A WEST TO
EAST FRONT DRAPED ACROSS THE REGION WILL PROVIDE CLOUDS AND
UNSETTLED WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST
ALONG THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF
PRECIPITATION ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING
CLOUDS AND A FEW MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY
SATURDAY. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT LAKES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY NIGHT/...MVFR CIG AT HIE AT 17Z TDA
WILL QUICKLY BECOME VFR AS CLOUDS DISSIPATE PER SATELLITE LOOP.
OTRW VFR THRU THIS EVE...THEN LOWERING TO MVFR/PSBL IFR IN
DEVELOPING RA LATER TNGT AND CONTINUING THRU TUESDAY MORNING OVER
NH AND INTO TUESDAY AFTERNOON OVER ME AS LOW PRES MOVES E FROM
THE GREAT LAKES AND THRU NRN NEW ENGLAND. IMPROVING WX TUESDAY
AFTERNOON AS THE LOW MOVES QUICKLY THRU THE GULF OF MAINE.
LONG TERM...
WED - THU...AREAS OF MVFR POSSIBLE IN RAIN SHOWERS.
FRI...MVFR LIKELY IN RAIN WITH LCL IFR POSSIBLE IN FOG.
SFC WND GUSTS TO 25 KT POSSIBLE VCNTY OF COAST.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...HIGH PRES MOVES E
THIS EVE FOLLOWED BY APPROACHING LOW PRES FROM THE GREAT LAKES
TNGT. THE LOW MOVES THRU NRN NEW ENGLAND TUESDAY MORNING THEN
QUICKLY THRU THE GULF OF MAINE TUESDAY AFTERNOON. PRES PATTERN
WEAK THIS EVE BUT INCREASES WITH THE PASSING LOW...BUT NOT ENOUGH
TO GENERATE SCA LEVEL WINDS. SEAS INCREASE WITH THE SYSTEM MOVING
THRU BUT NOT TO SCA LEVELS FOR MOST OF THE WATERS. THE OUTER MOST
WATERS MAY REACH THE 5 FT SCA CRITERIA FOR A BRIEF PERIOD AS THE
LOW MOVES BY.
LONG TERM...
THU NIGHT - FRI...SMALL CRAFT CONDITIONS ARE LIKELY.
&&
.FIRE WEATHER...
RAIN MOVING IN LATER TNGT THEN ENDING W TO E TUESDAY WILL PROVIDE
QPF OF 1/4 TO 1/2 INCH ACROSS MUCH OF THE REGION. DRY WX FOLLOWS
BRIEFLY TUESDAY EVE THEN MORE SHRA ACTIVITY MOVES IN FOR THE REST
OF THE WORK WEEK AS A FRONTAL SYSTEM FORMS AND REMAINS STAGNANT
OVER OR JUST S OF THE REGION...WITH THE BEST CHC FOR WIDESPREAD
SIGNIFICANT PRCP THURSDAY NGT THRU FRIDAY NGT. PRCP MOSTLY RA...
BUT SN OR MIXED RASN PSBL N/MT AREAS AND MAYBE EVEN FURTHER S LATE
IN THE WEEK. THE WET WX AND HIGH RH VALUES ALONG WITH FAIRLY WEAK
WINDS THRU FRIDAY SHOULD PROVIDE FOR VERY LOW FIRE DANGER.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
443 PM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES REGION TONIGHT
THEN MOVE QUICKLY ACROSS NORTHERN NEW ENGLAND AND THROUGH THE GULF
OF MAINE ON TUESDAY. THIS WILL GIVE US A PERIOD OF RAIN LATE
TONIGHT INTO TUESDAY WITH SNOW POSSIBLE OVER MORE NORTHERN AREAS.
THE LOW WILL MOVE QUICKLY OUT TO SEA TUESDAY EVENING AS FAIR
WEATHER SETTLES IN BRIEFLY. A FRONTAL SYSTEM SETS UP OVER THE
REGION AS LOW PRESSURE HEADS EAST ALONG IT TUESDAY NIGHT BRINGING
A CHANCE OF MORE RAIN LATE TUESDAY NIGHT. THE WEST TO EAST FRONT
DRAPED ACROSS THE REGION THEN PROVIDES CLOUDS AND UNSETTLED
WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST ALONG
THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF PRECIPITATION
ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING CLOUDS AND A FEW
MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY SATURDAY. HIGH PRESSURE
WILL BUILD EAST FROM THE GREAT LAKES FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATE...
THE SEA BREEZE SHOULD KICK IN ALONG THE IMMDIATE COASTLINE DURING
THE NEXT HOUR. HOWEVER...NW BREEZES ALLOWED PORTLAND TO TOP OUT AT
THEIR HIGHEST TEMPERATURE OF THE YEAR...REACHING 61 DEGREES.
LATEST RUC SHOWS PCPN REACHING WRN PTNS OF OUR FORECAST AREA
SHORTLY AFTER MIDNIGHT. IN THE MEANTIME...CLOUDS WILL OVERSPREAD
THE REGION THIS EVENING FROM WEST TO EAST.
MADE MINOR ADJUSTMENTS TO THE DEW POINT AND WIND FIELDS.
OTRW...LITTLE IN THE WAY OF CHANGES TO THE GRIDS.
PREV DISC...
SFC HIGH MOVES QUICKLY OUT TO SEA THIS EVE AS LOW PRES
MOVES E FROM THE GREAT LAKES REGION TNGT. THE LOW IS ASSOCIATED
WITH AN UPR LVL TROF THAT IS MOVING QUICKLY E THRU THE STRONG
WESTERLIES ALOFT. THE LOW WILL SPREAD CLOUDS THEN RA E INTO THE
FCST AREA OVERNIGHT. TEMP PROFILE MAY BE COLD ENOUGH FOR -SN OR
-RASN OVER OUR MORE NRN ZONES IN ME...IN PARTICULAR NRN FRANKLIN
AND CENTRAL SOMERSET COUNTIES AS WELL AS THE HIGHEST TERRAIN IN
THE WHITE MTS OF NRN NH. HOWEVER...ANY ACCUMULATION WILL BE LGT IF
ANY AT ALL.
TEMPS WILL STAY MILD RANGING FROM THE MID 30S N TO THE LOWER 40S S
EXCEPT FOR SOME LOWER 30S ACROSS FAR NRN ZONES WHERE THE -SN IS
PSBL. LGT WINDS WILL TURN TO AN EASTERLY DIRECTION AHEAD OF THE
APPROACHING LOW.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE NEAR TERM
FCST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
THE UPR LVL SHORT WAVE TROF MOVES QUICKLY TO THE E AS THE UPR LVL
FLOW CONTINUES VERY STRONG ON TUESDAY. THIS BRINGS THE SFC LOW
ACROSS NRN NEW ENGLAND TUESDAY MORNING AND THRU THE GULF OF MAINE
TUESDAY AFTERNOON. THIS WILL CONT RA...OR SN/MIXED RASN FAR NRN
ZONES INTO TUESDAY WITH DRIER WX AND SOME CLEARING TO FOLLOW
TUESDAY AFTERNOON OVER NH AND FROM MID TO LATE AFTERNOON OVER ME.
FAIR WX TUESDAY EVE IN THE WAKE OF THE LOW. HOWEVER...A FNT SETS
UP OVER THE REGION WITH WEAK LOW PRES APPROACHING FROM THE W. THIS
WILL BRING MORE CLOUDS BACK IN WITH A CHC OF RA LATE TUESDAY NGT.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE SHORT TERM
FCST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WE BEGIN THE PERIOD WITH A FLAT RIDGE TO OUR SOUTH AND AN UPPER
VORTEX OVER EASTERN CANADA WITH FORECAST AREA JUST TO THE SOUTH OF
THE MEAN JET AXIS. UPSTREAM...AN UPPER TROUGH WILL BE SITUATED
JUST TO THE LEE OF THE ROCKIES. THAT UPPER TROUGH LIFTS OUT INTO
THE GREAT LAKES BY LATE IN THE WORKWEEK WHEN FORECAST CONFIDENCE
DIMINISHES IN INCREASING MODEL SPREAD. IN THE DAILIES...A WEST TO
EAST FRONT DRAPED ACROSS THE REGION WILL PROVIDE CLOUDS AND
UNSETTLED WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST
ALONG THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF
PRECIPITATION ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING
CLOUDS AND A FEW MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY
SATURDAY. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT LAKES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY NIGHT/...MVFR CIG AT HIE AT 17Z TDA
WILL QUICKLY BECOME VFR AS CLOUDS DISSIPATE PER SATELLITE LOOP.
OTRW VFR THRU THIS EVE...THEN LOWERING TO MVFR/PSBL IFR IN
DEVELOPING RA LATER TNGT AND CONTINUING THRU TUESDAY MORNING OVER
NH AND INTO TUESDAY AFTERNOON OVER ME AS LOW PRES MOVES E FROM
THE GREAT LAKES AND THRU NRN NEW ENGLAND. IMPROVING WX TUESDAY
AFTERNOON AS THE LOW MOVES QUICKLY THRU THE GULF OF MAINE.
LONG TERM...
WED - THU...AREAS OF MVFR POSSIBLE IN RAIN SHOWERS.
FRI...MVFR LIKELY IN RAIN WITH LCL IFR POSSIBLE IN FOG.
SFC WND GUSTS TO 25 KT POSSIBLE VCNTY OF COAST.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...HIGH PRES MOVES E
THIS EVE FOLLOWED BY APPROACHING LOW PRES FROM THE GREAT LAKES
TNGT. THE LOW MOVES THRU NRN NEW ENGLAND TUESDAY MORNING THEN
QUICKLY THRU THE GULF OF MAINE TUESDAY AFTERNOON. PRES PATTERN
WEAK THIS EVE BUT INCREASES WITH THE PASSING LOW...BUT NOT ENOUGH
TO GENERATE SCA LEVEL WINDS. SEAS INCREASE WITH THE SYSTEM MOVING
THRU BUT NOT TO SCA LEVELS FOR MOST OF THE WATERS. THE OUTER MOST
WATERS MAY REACH THE 5 FT SCA CRITERIA FOR A BRIEF PERIOD AS THE
LOW MOVES BY.
LONG TERM...
THU NIGHT - FRI...SMALL CRAFT CONDITIONS ARE LIKELY.
&&
.FIRE WEATHER...
RAIN MOVING IN LATER TNGT THEN ENDING W TO E TUESDAY WILL PROVIDE
QPF OF 1/4 TO 1/2 INCH ACROSS MUCH OF THE REGION. DRY WX FOLLOWS
BRIEFLY TUESDAY EVE THEN MORE SHRA ACTIVITY MOVES IN FOR THE REST
OF THE WORK WEEK AS A FRONTAL SYSTEM FORMS AND REMAINS STAGNANT
OVER OR JUST S OF THE REGION...WITH THE BEST CHC FOR WIDESPREAD
SIGNIFICANT PRCP THURSDAY NGT THRU FRIDAY NGT. PRCP MOSTLY RA...
BUT SN OR MIXED RASN PSBL N/MT AREAS AND MAYBE EVEN FURTHER S LATE
IN THE WEEK. THE WET WX AND HIGH RH VALUES ALONG WITH FAIRLY WEAK
WINDS THRU FRIDAY SHOULD PROVIDE FOR VERY LOW FIRE DANGER.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1235 PM EDT MON APR 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW
PRESSURE WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1234 PM...MADE SOME MINOR TWEAKS TO THE SKY/TEMP/WIND GRIDS BASED
ON THE NOON EDT/16Z OBSERVATIONS AND THE LATEST SATELLITE
PICTURES.
920 AM UPDATE...HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY.
THE SKY RANGES FROM CLEAR ALONG THE COAST TO CLOUDY ACROSS MOST OF
NORTHERN MAINE. MADE SOME ADJUSTMENTS TO LOWER THE CLOUD COVER
THIS MORNING ALONG THE COAST. CLOUDS ACROSS THE NORTH WILL
GRADUALLY BREAK UP OVER THE NEXT FEW HOURS AS DRIER AIR AT MID
LEVELS (EVIDENT ON THE 12Z KCAR SOUNDING) BEGINS TO MIX INTO THE
LOWER LEVELS. ADJUSTED TEMPERATURES UP BY A FEW DEGREES ACROSS THE
NORTHERN ZONES WHERE A FEW SPOTS ARE ALREADY WITHIN A DEGREE OR
TWO OF FORECAST HIGHS. ALSO MADE SOME MINOR ADJUSTMENTS TO
INCREASE THE WIND GUSTS A BIT TODAY.
UPDATE 0717 EDT: HAVE ADJUSTED TEMPERATURE...NO OTHER CHANGES.
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
NEAR TERM: STILL LINGERING AREAS WITH MVFR CEILINGS ACROSS THE
NORTHERN TERMINALS. THE CLOUDS WILL THIN OUT THIS AFTERNOON WITH
ALL AREAS BECOMING VFR BY EALY-MID AFTERNOON. EXPECT VFR
CONDITIONS INTO TONIGHT...LOWERING TO IFR/MVFR TOWARD MORNING IN
RAIN AT THE SOUTHERN TERMINALS.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: THE WIND HAS DIMINISHED TO AROUND 10 KT AND THE SEAS
HAVE SUBSIDED TO UNDER 5 FT AND THEREFORE THE SCA WAS CANCELLED.
THE WIND AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA
THROUGH TONIGHT.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...CB/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...CB/MIGNONE
MARINE...CB/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
921 AM EDT MON APR 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW
PRESSURE WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
920 AM UPDATE...HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY.
THE SKY RANGES FROM CLEAR ALONG THE COAST TO CLOUDY ACROSS MOST OF
NORTHERN MAINE. MADE SOME ADJUSTMENTS TO LOWER THE CLOUD COVER
THIS MORNING ALONG THE COAST. CLOUDS ACROSS THE NORTH WILL
GRADUALLY BREAK UP OVER THE NEXT FEW HOURS AS DRIER AIR AT MID
LEVELS (EVIDENT ON THE 12Z KCAR SOUNDING) BEGINS TO MIX INTO THE
LOWER LEVELS. ADJUSTED TEMPERATURES UP BY A FEW DEGREES ACROSS THE
NORTHERN ZONES WHERE A FEW SPOTS ARE ALREADY WITHIN A DEGREE OR
TWO OF FORECAST HIGHS. ALSO MADE SOME MINOR ADJUSTMENTS TO
INCREASE THE WIND GUSTS A BIT TODAY.
UPDATE 0717 EDT: HAVE ADJUSTED TEMPERATURE...NO OTHER CHANGES.
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MVFR AT THE NORTHERN TERMINALS SHOULD GIVE WAY TO VFR
BY EARLY THIS AFTERNOON. EXPECT VFR CONDITIONS INTO TONIGHT.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: THE WIND HAS DIMINISHED TO AROUND 10 KT AT THE EASTERN
MAINE SHELF. SEAS STILL RUNNING AT 6 FT WITH A 6 SEC PERIOD...SO
WILL MAINTAIN THE SCA FOR A COUPLE MORE HOURS. WAVE SYSTEM IS
FROM SOUTH-SOUTHWEST WITH SECONDARY LONGER PERIOD WAVE OUT OF
SOUTHEAST. SINCE PRIMARY WAVE GROUP WITH SOUTHWEST COMPONENT
EXPECT WAVES TO SUBSIDE SHORTLY AFTER WINDS LATER THIS MORNING SO
1500Z TIMING TO END SCA STILL LOOKS GOOD.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...CB/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...CB/MIGNONE
MARINE...CB/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
718 AM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW PRESSURE
WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE 0717 EDT: HAVE ADJUSTED TEMPERATURE...NO OTHER CHANGES.
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
NEAR TERM: EXPECT VFR CONDITIONS BY LATER THIS MORNING AND
CONTINUING VFR TONIGHT.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: FOR WINDS: HAVE BLENDED THE NAM12 AND GFS40 FOR
SUSTAIN WINDS AND WILL USE 125 PERCENT OF SUSTAINED WIND FOR GUST
SPEED. FOR WAVES: PRIMARY WAVE SYSTEM IS FROM SOUTH-SOUTHWEST WITH
SECONDARY LONGER PERIOD WAVE OUT OF SOUTHEAST. SINCE PRIMARY WAVE
GROUP WITH SOUTHWEST COMPONENT EXPECT WAVES TO SUBSIDE SHORTLY
AFTER WINDS LATER THIS MORNING SO 1500Z TIMING TO END SCA STILL
LOOKS GOOD.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
706 PM EDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 438 PM EDT MON APR 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
TROUGH OVER NORTHERN LOWER MICHIGAN WHICH SUPPORTED A
DEFORMATION/FGEN BAND OF PCPN (RAIN/SLEET) OVER CNTRL UPPER MI ON
ITS NORTHWEST FLANK. RADAR INDICATED THAT THE BAND WAS MOVING
STEADILY OFF TO THE ENE WHICH SHOULD BRING AN END TO THE PCPN OVER
CNTRL UPPER MI BY LATE AFTERNOON AND OVER THE ERN CWA THIS EVENING.
AT THE SFC...THE MAIN FRONTAL BOUNDARY STRETCHED FROM NRN IA INTO SRN
LOWER MI. EASTERLY FLOW PREVAILED ACROSS UPPER MI AHEAD OF AN
INVERTED TROUGH OVER ERN MN.
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION AREAS
OF FOG ARE EXPECTED. WEAK ENE TO NE UPSLOPE...STILL MAY SUPPORT SOME
-DZ/-FZDZ OVERNIGHT OVER THE NORTH. THE CLOUDS SHOULD BE THICK
ENOUGH TO KEEP TEMPS TOWARD THE HIGHER END OF GUIDANCE...AROUND 30.
ANOTHER AREA OF PCPN DEVELOPING OVER THE PLAINS IS EXPECTED TO
SPREAD INTO THE WESTERN GREAT LAKES AS THE AREA FALLS UNDER THE
RIGHT ENTRANCE OF AN UPPER LEVEL JET STREAK MOVING THROUGH NRN
ONTARIO INTO QUEBEC. A BROAD AREA OF ISENTROPIC LIFT NORTH OF THE
WARM FRONT WILL BRING THE EXPANDING PCPN THROUGH WI TOWARD UPPER MI
BY MIDDAY TUE. ALTHOUGH THE MODELS HAVE TRENDED A BIT FARTHER NORTH
WITH THE PCPN AREA...EXPECT THAT THERE MAY STILL BE A SHARP NRN EDGE
TO THE PCPN THROUGH UPPER MI GIVEN THE DRIER ACYC NRLY 850-700 FLOW
FROM NRN ONTARIO INTO THE AREA. SO...POPS WERE TAPERED OFF
SIGNIFICANTLY FROM SOUTH TO NORTH. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET WILL BE POSSIBLE...EXCEPT OVER THE FAR SOUTH WHERE
SFC TEMPS CLIMB INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 PM EDT MON APR 8 2013
A 500MB RIDGE WILL BE OVERHEAD TUESDAY NIGHT THROUGH THURSDAY
MORNING. HOWEVER...WITH SIZABLE LOWS TO OUR NORTH AND
SOUTHWEST...SIGNIFICANT WEATHER WILL BE NEARBY.
850MB TEMPS 0F -1 TO -4C TUESDAY NIGHT...AND A GOOD FEED OF MOISTURE
INTO S CENTRAL UPPER MICHIGAN WILL KEEP A CHANCE OF PRECIPITATION IN
THE AREA. WHILE THE LOWEST LEVELS BELOW 900MB SHOULD BE FAIRLY
SATURATED...BOTH THE NAM AND GFS INDICATE A LAYER OF DRY AIR AROUND
800-850MB...WITH MOISTURE ABOVE THAT LAYER REACHING THE DGZ WHICH
SHOULD BE HOVERING NEAR 500MB. SFC TEMPS NEAR OR SLIGHTLY BELOW
FREEZING DOES NOT MAKE THIS FORECAST ANY EASIER. AT THIS
POINT...WITH THE LACK OF DEPTH TO THE THIN DRY LAYER...IT STILL
LOOKS LIKE SNOW WILL BE THE BEST BET. THE BEST CHANCE OF SNOW WILL
REMAIN SOUTH. IF THE NAM IS RIGHT THOUGH...THERE WILL BE NEARLY
CONSTANT SLEET FROM LATE TUESDAY NIGHT THROUGH AT LEAST THURSDAY.
THE 500MB RIDGE WILL BE PUSHED EAST ON THURSDAY...WITH STRONGER E-NE
WINDS /40-55KTS AT 850MB/ AND POTENTIALLY MERGING SOUTHERN AND
NORTHERN STREAM SYSTEMS. WHILE THE 08/12Z GFS INDICATES MORE OF A
MERGER...THE 12/00Z ECMWF PUSHES THE NORTHERN LOW OFF THE EASTERN
COAST OF CANADA BEFORE THE LOW FROM THE CENTRAL PLAINS CAN MOVE
ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT INTO FRIDAY. THE ECMWF
LOOKS TO BE A BIT ON ITS OWN AT THIS POINT WITH THE 500MB LOW
SPINNING ACROSS UPPER MICHIGAN FRIDAY AND FRIDAY NIGHT...BEFORE
SLIDING EAST. THE CANADIAN AND GFS ARE MORE PROGRESSIVE WITH THE
FEATURE.
NO MATTER WHAT SOLUTION...OR GROUP OF SOLUTIONS IS PREFERRED...IT
LOOKS LIKE HEADLINE WORTHY SNOW WILL BE PUSHING BACK IN. CURRENTLY
HAVE AN INITIAL FORECAST OF NEAR HALF AN INCH OF LIQUID FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING...EQUATING TO 6 OR MORE
INCHES OF HEAVY WET SNOW FOR AREAS SOUTHWEST OF A LINE FROM
ONTONAGON TO SIDNAW AND IRON MOUNTAIN. GIVEN THE FAVORABLE UPSLOPE
FLOW...INCREASED POPS AND QPF FOR THE HIGHER ELEVATIONS OF WESTERN
BARAGA TO EASTERN MARQUETTE COUNTY NEAR LAKE SUPERIOR. COLDER AIR
/850MB TEMPS OF -10C OR COOLER/ WILL LIKELY SLIDE IN FROM DAYBREAK
FRIDAY ON. THE ECMWF HAS ANOTHER HALF INCH TO THREE QUARTERS OF
LIQUID NOT INCLUDED IN THE ABOVE TOTALS...WITH THE MORE WRAPPED UP
AND SLOWER SOLUTION. WILL NEED TO WAIT UNTIL MODELS COME IN BETTER
AGREEMENT BEFORE MAKING ANY MORE CRITICAL EVALUATIONS.
ALL SEEMS TO RIGHT WITH THE WORLD AGAIN BRIEFLY SATURDAY
AFTERNOON...WITH THE MODELS IN BETTER AGREEMENT. EXPECT THE 500MB
LOW TO BE NEAR THE ONTARIO/QUEBEC BORDER...WITH RIDGING ACROSS
MINNESOTA PUSHING INTO WESTERN UPPER MICHIGAN. THIS IS SHORT
LIVED...AS THE GFS AND ECMWF COME OUT OF PHASE AGAIN BY SUNDAY
THANKS TO THE SLOWER ECMWF SOLUTION. GIVEN THE SIGNIFICANT
UNCERTAINTY FOR SATURDAY NIGHT THROUGH THE END OF THE FORECAST
PERIOD...FEW LARGE SCALE CHANGES WILL BE MADE TO DEVIATE FROM THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 706 PM EDT MON APR 8 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
LIFR/VLIFR CONDITIONS WILL PERSIST THROUGH TUE MORNING AT ALL SITES.
AS DRIER AIR TRIES TO COME IN TUE MORNING AT CMX AND
IWD...CONDITIONS WILL IMPROVE TO VFR. AT SAW...LOW LEVEL MOISTURE
WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO KEEP THE LOW CIGS IN
THROUGH THE REST OF THE FORECAST PERIOD. AT CMX...TEMPERATURES ARE
COLD ENOUGH FOR A LITTLE FREEZING DRIZZLE OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT MON APR 8 2013
A WEAK TROUGH WILL MOVE INTO LAKE SUPERIOR TONIGHT WITH MAINLY LIGHT
WINDS. FROM TUESDAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN
BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH.
PRES GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND
25 KT TUE AND AT OR ABOVE 25 KTS TOWARD MID WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
439 PM EDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 438 PM EDT MON APR 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
TROUGH OVER NORTHERN LOWER MICHIGAN WHICH SUPPORTED A
DEFORMATION/FGEN BAND OF PCPN (RAIN/SLEET) OVER CNTRL UPPER MI ON
ITS NORTHWEST FLANK. RADAR INDICATED THAT THE BAND WAS MOVING
STEADILY OFF TO THE ENE WHICH SHOULD BRING AN END TO THE PCPN OVER
CNTRL UPPER MI BY LATE AFTERNOON AND OVER THE ERN CWA THIS EVENING.
AT THE SFC...THE MAIN FRONTAL BOUNDARY STRETCHED FROM NRN IA INTO SRN
LOWER MI. EASTERLY FLOW PREVAILED ACROSS UPPER MI AHEAD OF AN
INVERTED TROUGH OVER ERN MN.
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION AREAS
OF FOG ARE EXPECTED. WEAK ENE TO NE UPSLOPE...STILL MAY SUPPORT SOME
-DZ/-FZDZ OVERNIGHT OVER THE NORTH. THE CLOUDS SHOULD BE THICK
ENOUGH TO KEEP TEMPS TOWARD THE HIGHER END OF GUIDANCE...AROUND 30.
ANOTHER AREA OF PCPN DEVELOPING OVER THE PLAINS IS EXPECTED TO
SPREAD INTO THE WESTERN GREAT LAKES AS THE AREA FALLS UNDER THE
RIGHT ENTRANCE OF AN UPPER LEVEL JET STREAK MOVING THROUGH NRN
ONTARIO INTO QUEBEC. A BROAD AREA OF ISENTROPIC LIFT NORTH OF THE
WARM FRONT WILL BRING THE EXPANDING PCPN THROUGH WI TOWARD UPPER MI
BY MIDDAY TUE. ALTHOUGH THE MODELS HAVE TRENDED A BIT FARTHER NORTH
WITH THE PCPN AREA...EXPECT THAT THERE MAY STILL BE A SHARP NRN EDGE
TO THE PCPN THROUGH UPPER MI GIVEN THE DRIER ACYC NRLY 850-700 FLOW
FROM NRN ONTARIO INTO THE AREA. SO...POPS WERE TAPERED OFF
SIGNIFICANTLY FROM SOUTH TO NORTH. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET WILL BE POSSIBLE...EXCEPT OVER THE FAR SOUTH WHERE
SFC TEMPS CLIMB INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 PM EDT MON APR 8 2013
A 500MB RIDGE WILL BE OVERHEAD TUESDAY NIGHT THROUGH THURSDAY
MORNING. HOWEVER...WITH SIZABLE LOWS TO OUR NORTH AND
SOUTHWEST...SIGNIFICANT WEATHER WILL BE NEARBY.
850MB TEMPS 0F -1 TO -4C TUESDAY NIGHT...AND A GOOD FEED OF MOISTURE
INTO S CENTRAL UPPER MICHIGAN WILL KEEP A CHANCE OF PRECIPITATION IN
THE AREA. WHILE THE LOWEST LEVELS BELOW 900MB SHOULD BE FAIRLY
SATURATED...BOTH THE NAM AND GFS INDICATE A LAYER OF DRY AIR AROUND
800-850MB...WITH MOISTURE ABOVE THAT LAYER REACHING THE DGZ WHICH
SHOULD BE HOVERING NEAR 500MB. SFC TEMPS NEAR OR SLIGHTLY BELOW
FREEZING DOES NOT MAKE THIS FORECAST ANY EASIER. AT THIS
POINT...WITH THE LACK OF DEPTH TO THE THIN DRY LAYER...IT STILL
LOOKS LIKE SNOW WILL BE THE BEST BET. THE BEST CHANCE OF SNOW WILL
REMAIN SOUTH. IF THE NAM IS RIGHT THOUGH...THERE WILL BE NEARLY
CONSTANT SLEET FROM LATE TUESDAY NIGHT THROUGH AT LEAST THURSDAY.
THE 500MB RIDGE WILL BE PUSHED EAST ON THURSDAY...WITH STRONGER E-NE
WINDS /40-55KTS AT 850MB/ AND POTENTIALLY MERGING SOUTHERN AND
NORTHERN STREAM SYSTEMS. WHILE THE 08/12Z GFS INDICATES MORE OF A
MERGER...THE 12/00Z ECMWF PUSHES THE NORTHERN LOW OFF THE EASTERN
COAST OF CANADA BEFORE THE LOW FROM THE CENTRAL PLAINS CAN MOVE
ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT INTO FRIDAY. THE ECMWF
LOOKS TO BE A BIT ON ITS OWN AT THIS POINT WITH THE 500MB LOW
SPINNING ACROSS UPPER MICHIGAN FRIDAY AND FRIDAY NIGHT...BEFORE
SLIDING EAST. THE CANADIAN AND GFS ARE MORE PROGRESSIVE WITH THE
FEATURE.
NO MATTER WHAT SOLUTION...OR GROUP OF SOLUTIONS IS PREFERRED...IT
LOOKS LIKE HEADLINE WORTHY SNOW WILL BE PUSHING BACK IN. CURRENTLY
HAVE AN INITIAL FORECAST OF NEAR HALF AN INCH OF LIQUID FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING...EQUATING TO 6 OR MORE
INCHES OF HEAVY WET SNOW FOR AREAS SOUTHWEST OF A LINE FROM
ONTONAGON TO SIDNAW AND IRON MOUNTAIN. GIVEN THE FAVORABLE UPSLOPE
FLOW...INCREASED POPS AND QPF FOR THE HIGHER ELEVATIONS OF WESTERN
BARAGA TO EASTERN MARQUETTE COUNTY NEAR LAKE SUPERIOR. COLDER AIR
/850MB TEMPS OF -10C OR COOLER/ WILL LIKELY SLIDE IN FROM DAYBREAK
FRIDAY ON. THE ECMWF HAS ANOTHER HALF INCH TO THREE QUARTERS OF
LIQUID NOT INCLUDED IN THE ABOVE TOTALS...WITH THE MORE WRAPPED UP
AND SLOWER SOLUTION. WILL NEED TO WAIT UNTIL MODELS COME IN BETTER
AGREEMENT BEFORE MAKING ANY MORE CRITICAL EVALUATIONS.
ALL SEEMS TO RIGHT WITH THE WORLD AGAIN BRIEFLY SATURDAY
AFTERNOON...WITH THE MODELS IN BETTER AGREEMENT. EXPECT THE 500MB
LOW TO BE NEAR THE ONTARIO/QUEBEC BORDER...WITH RIDGING ACROSS
MINNESOTA PUSHING INTO WESTERN UPPER MICHIGAN. THIS IS SHORT
LIVED...AS THE GFS AND ECMWF COME OUT OF PHASE AGAIN BY SUNDAY
THANKS TO THE SLOWER ECMWF SOLUTION. GIVEN THE SIGNIFICANT
UNCERTAINTY FOR SATURDAY NIGHT THROUGH THE END OF THE FORECAST
PERIOD...FEW LARGE SCALE CHANGES WILL BE MADE TO DEVIATE FROM THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 151 PM EDT MON APR 8 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PALCE AND UPSLOPE EASTERLY FLOW
CONTINUING THIS AFTERNOON...EXPECT VLIFR CONDITION WILL PERSIST AT
CMX INTO TONIGHT. SOME IMPROVEMENT MAY BE POSSIBLE LATE TONIGHT INTO
TUE MORNING WHEN WINDS BECOME NNW REDUCING THE UPSLOPE COMPONENT.
AT SAW...RAIN MIXED WITH SNOW AND EAST WINDS SHOULD ALSO DROP
CONDITIONS TO IFR THIS AFTERNOON AND TO LIFR LATE THIS AFTERNOON OR
EVENING. E WINDS VEERING N SHOULD KEEP CONDITIONS FROM IMPROVING
MUCH TIL TUE MORNING.
AT IWD...ENOUGH LOW LEVEL MOISTURE WILL LINGER OVER THE AREA SO THAT
MVFR CIGS ARE EXPECTED TO FALL TO IFR THIS AFTERNOON AND TONIGHT AS WINDS
BECOME NORTHERLY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT MON APR 8 2013
A WEAK TROUGH WILL MOVE INTO LAKE SUPERIOR TONIGHT WITH MAINLY LIGHT
WINDS. FROM TUESDAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN
BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH.
PRES GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND
25 KT TUE AND AT OR ABOVE 25 KTS TOWARD MID WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
345 PM EDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 345 PM EDT MON APR 8 2013
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED THIS
WEEK AS AN ACTIVE FRONTAL BOUNDARY REMAINS NEARLY STATIONARY JUST
SOUTH OF MICHIGAN. WIDESPREAD RAINFALL AMOUNTS OF THREE OR MORE
INCHES ARE POSSIBLE BY THE END OF THE WEEK.
A THREAT FOR FREEZING RAIN... SLEET AND SNOW WILL ALSO DEVELOP
WEDNESDAY NIGHT AND LINGER THROUGH FRIDAY... MAINLY ALONG AND NORTH
OF THE INTERSTATE 96 CORRIDOR... AS COLD AIR ASSOCIATED WITH A
CANADIAN HIGH PRESSURE AREA COMES DOWN FROM THE NORTH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 PM EDT MON APR 8 2013
WIND ADVISORY REMAINS IN EFFECT UNTIL 8 PM. THE CENTER OF THE
COMPACT/IMPRESSIVE SFC LOW WAS NEAR MKG AT 3 PM AND EVEN HAS AN
"EYE" ASSOCIATED WITH IT ON VISIBLE SATELLITE IMAGERY. RUC RAPID
REFRESH HAS BEEN SHOWING SFC WIND GUSTS TO 45 MPH ALONG AND SOUTH OF
THE I-96 CORRIDOR THROUGH EARLY EVENING ON THE SRN PERIPHERY OF THIS
SFC LOW. SFC TEMPS IN THE MID 60S IN THE WARM SECTOR COMBINED WITH
PARTIAL CLEARING WILL YIELD DEEPER MIXING TO BRING THE STRONG GUSTS
DOWN TO THE SFC. THE SHOWER THREAT WITH THIS INITIAL WAVE WAS
ENDING/EXITING TO THE NORTHEAST THIS AFTERNOON. TONIGHT SHOULD BE
MOSTLY DRY IN THE SUBSIDENCE BEHIND IT.
MOIST GROUND LEFT OVER BY THIS MORNINGS RAIN COMBINED WITH
DIMINISHING WINDS AND PERIOD OF DECREASING CLOUDS WILL BRING THE
POTENTIAL FOR AREAS OF FOG LATER TONIGHT. CLOUDS SHOULD BE
INCREASING AGAIN THOUGH AHEAD OF THE NEXT APCHG WAVE TOWARD DAYBREAK.
WILL CARRY CATEGORICAL POPS IN ALL FCST PERIODS FROM TUESDAY THROUGH
WEDNESDAY NIGHT AS FAVORABLE WET SYNOPTIC PATTERN PERSISTS. WE
CONTINUE TO BE IN THE RIGHT ENTRANCE REGION OF THE 150 KT UPR JET
CORE IN SRN CANADA... WITH STRONG MID LEVEL FGEN FORCING ALONG A
VERY TIGHT BAROCLINIC ZONE. ELEVATED INSTABILITY AND A PERSISTENT
40+ KT LOW LEVEL JET EAST OF THE DEEP LONGWAVE TROUGH OVER THE WRN
U.S. SHOULD RESULT IN PERIODS OF POTNL TSTMS AS WELL.
SVR WX THREAT REMAINS VERY LOW SINCE THE SFC BOUNDARY REMAINS MOSTLY
SOUTH OF MI. HOWEVER SOME EPISODES OF SMALL HAIL AND/OR LOCALLY
HEAVY
RAINFALL ARE CERTAINLY POSSIBLE. FEEL NO NEED FOR ANY FLOOD
HEADLINES IN THE SHORT TERM GIVEN THE RECENT DRY CONDITIONS... BUT
NUISANCE FLOODING COULD BECOME AN ISSUE BY MID WEEK DEPENDING ON HOW
MUCH RAIN WE SEE FROM THE NEXT FEW WAVES.
FREEZING RAIN/SLEET/SNOW BECOMES A CONCERN BY LATE WEDNESDAY NIGHT
IN
THE NRN CWFA AS THE COLD LOW LEVEL AIR MASS ASSOCIATED WITH THE
HUDSON BAY HIGH STARTS TO INFILTRATE THE REGION FROM THE NORTHEAST.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 PM EDT MON APR 8 2013
UNSETTLED WX WILL CONTINUE THURSDAY AS THE SLOW MOVING LOW PRESSURE
SYSTEM CONTINUES TO IMPACT OUR REGION. RAIN IS EXPECTED NEAR TO
SOUTH OF I-96 THURSDAY AND THERE IS POTENTIAL FOR A RAIN SNOW MIX
ACROSS OUR NORTHERN COUNTIES THURSDAY WITH NE FLOW CAA WITH HIGH
PRESSURE OVER JAMES BAY.
NE TO NORTH FLOW CAA ACROSS OUR AREA THURSDAY NIGHT WILL RESULT IN
POTENTIAL FOR LIGHT SNOW OR A LIGHT RAIN/LIGHT SNOW MIX. ALSO CANNOT
RULE OUT SOME (LIGHT) FREEZING RAIN THURSDAY EVENING GIVEN THIS
SYNOPTIC SETUP WITH THE HIGH PRESSURE TO OUR NORTH AND SHALLOW LOW
LEVEL COLD AIR IN PLACE.
SOME LIGHT PCPN MAY EVEN LINGER INTO FRIDAY BEFORE A MORE TRANQUIL
WX PATTERN FINALLY DEVELOPS FRIDAY NIGHT THROUGH THE WEEKEND AS HIGH
PRESSURE BUILDS IN. TEMPS WILL COOL TO AROUND TEN DEGREES BELOW
NORMAL ON THE BACK SIDE OF THAT LOW PRESSURE SYSTEM LATE THURSDAY
THROUGH SATURDAY BEFORE RETURNING TO CLOSER TO NORMAL BY LATE IN THE
WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1230 PM EDT MON APR 8 2013
WINDY CONDITIONS ARE EXPECTED TO DEVELOP AT MOST OF THE TERMINALS
DURING THE MID TO LATE AFTERNOON HOURS AS SOME PARTIAL CLEARING
DEVELOPS AND ALLOWS FOR WIND GUSTS TO POTENTIALLY REACH 40 TO 45 KTS
MID TO LATE AFTERNOON OUT OF THE SOUTH TO SOUTHWEST. WIND SPEEDS
WILL DIMINISH QUICKLY EARLY THIS EVENING.
IFR/MVFR CONDITIONS ARE ANTICIPATED THIS AFTERNOON WITH SCATTERED
SHOWERS. CONDITIONS WILL GRADUALLY DETERIORATE TO IFR/LIFR LATE
TONIGHT AS PARTIAL CLEARING AND ALL THE MOISTURE FROM RAINFALL
EARLIER TODAY ALLOWS FOG TO DEVELOP.
CONDITIONS WILL REMAIN IFR/LIFR TUESDAY MORNING WITH RAIN
OVERSPREADING ALL THE TERMINALS FROM SW TO NE DURING THE MID TO LATE
MORNING HOURS.
&&
.MARINE...
ISSUED AT 345 PM EDT MON APR 8 2013
SMALL BUT STRONG AREA OF LOW PRESSURE MOVING FROM MUSKEGON TO THE
SAGINAW BAY THROUGH EARLY EVENING WILL BRING PERIOD OF STRONG/GUSTY
WESTERLY WINDS MAINLY SOUTH OF WHITEHALL. WINDS/WAVES SUBSIDING
QUICKLY AFTER 8 PM. AFTER THIS EVENING... WINDS WILL BE MOSTLY
OFFSHORE THROUGH THE WEEK BUT STILL STRONG AT TIMES.
&&
.HYDROLOGY...
ISSUED AT 345 PM EDT MON APR 8 2013
THE WAVE THIS MORNING PRODUCED AROUND ONE HALF INCH OF RAIN WHICH IS
NOT ENOUGH TO CAUSE ANY HYDRO ISSUES. HOWEVER THE POTENTIAL EXISTS
FOR ANOTHER THREE OR MORE INCHES OF RAIN THROUGH THE END OF THE WEEK
AND THE HYDRO SITUATION WILL NEED TO BE CLOSELY MONITORED.
FORTUNATELY THE RIVERS ARE EXTREMELY LOW RIGHT NOW AND CAN HANDLE
QUITE A BIT OF RAINFALL... ESPECIALLY IF IT IS SPACED OUT OVER
SEVERAL DAYS. THE REALITY OF IT IS THAT WE REALLY NEED ALL THIS RAIN
TO GET THE RIVERS OUT OF NEAR RECORD LOW STAGES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ050-056>059-
064>067-071>074.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR LMZ844>848.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
345 PM CDT MON APR 8 2013
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE BOUNDARY LAYER HAS CONTINUED TO MOISTEN TODAY WITH SURFACE DEW
POINTS CURRENTLY IN THE MID 50S TO LOWER 60S. THIS MOISTURE COMBINED
WITH HEATING HAS RESULTED IN MODEST INSTABILITY WITH SBCAPES OF
AROUND 1200-1700 J/KG. SPC MESOANALYSIS SHOWS THERE IS ONLY WEAK
CIN ACROSS THE NRN 2/3RDS OF THE CWA AND MOST OF THE REGION HAS
EXTENSIVE CU. DESPITE THIS...THE APPARENT LACK OF A LOW LEVEL
FORCING MECHANISM/BOUNDARY HAS INHIBITED CONVECTION. MODEL QPFS
ARE OF LITTLE USE EARLY IN THE PERIOD OWING TO OVERDONE SURFACE
DEW POINTS AND INSTABILITY AND CONVECTIVE PCPN WITHIN THE MODELS.
THIS INCLUDES THE EXPLICIT CONVECTION ALLOWING MODELS. THE LATEST
SATELLITE IMAGERY SUGGESTS THE DEEPEST AND MOST AGITATED CU FIELD
RESIDES ACROSS NORTHERN MO INTO WEST CENTRAL IL AND THIS IS WHERE
THE HIGHEST POPS WILL BE FORECAST THIS EVENING. WATER VAPOR
IMAGERY AND THE RUC SHOWS SOME MINOR MID LEVEL PURTURBATIONS
UPSTREAM ACROSS THE PLAINS WHICH WILL SKIRT THIS REGION LATER
TONIGHT AND THUS NORTHERN MO INTO WEST CENTRAL IL WILL HAVE THE
HIGHEST POPS OVERNIGHT AS WELL. OVERNIGHT LOWS WILL BE QUITE MILD.
TUESDAY IS EXPECTED TO BE LARGELY DRY. THERE COULD BE SOME
RESIDUAL SHOWERS AND THUNDERSTORMS ACROSS THE FAR NORTHERN CWA IN
THE MORNING...HOWEVER THE ABSENCE OF A FOCUSING BOUNDARY AND A
STRENGTHENING EML SUGGESTS ANY OTHER CONVECTIVE POTENTIAL WILL BE
QUITE LOW AND ISOLATED. MORE IMPORTANTLY WE WILL SEE YET ANOTHER
DAY OF SEASONABLY WARM TEMPERATURES. DESPITE A GOOD DEAL OF
CU...HIGHS SHOULD RISE INTO MID 70S TO LOWER 80S.
GLASS
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE PERIOD FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT STILL APPEARS TO
BE QUITE ACTIVE. STILL THINKING THAT DISCRETE STORMS/CLUSTERS THAT
DEVELOP ALONG THE PLAINS COLD FRONT AND DRYLINE IN THE AFTERNOON
WILL QUICKLY GROW UPSCALE INTO A LINE/QLCS CONSIDERING THE DEEP
LAYER SHEAR VECTORS WITH ONLY A SMALL ANGLE FROM THE
BOUNDARY/FORCING. THE UPPER TROF WILL BE ONLY SLOWLY PROGRESSIVE
AS IT BECOMES MORE ELONGATED WHEN THE INITIAL UPPER LOW LIFTS NNE
AND ANOTHER SHORTWAVE DIGGS THRU THE BASE. THE NET EFFECT IS
BACKING OF THE UPPER LEVEL FLOW AND POTENTIAL SLOWING OF THE
EASTWARD MOVEMENT OF THE LINE/QLCS OVERNIGHT TUESDAY. THE NAM/CMC
GEM HAVE SLOWED CONSIDERABLY...HOWEVER THE ECMWF AND GFS CONTINUE
TO HAVE A GOOD DEAL OF QPF INTO EASTERN MO. WITH THIS IN MIND I
HAVENT MADE ANY RADICAL CHANGES. AMPLE INSTABILITY AND STRONG DEEP
LAYER SHEAR CONTINUE TO SUPPORT A SEVERE THREAT WITH ANY
THUNDERSTORMS. THE OVERALL EVOLUTION OF STORMS ON WED/WED NIGHT IS
A BIT UNCERTAIN DUE TO UNKNOWNS OF THE OVERNIGHT STORMS ON TUESDAY
NIGHT. THE COLD FRONT WILL BE SLOWLY MOVING ACROSS THE AREA AND
DEEP LAYER FORCING BOTH AHEAD AND BEHIND THE FRONT WILL BE
INCREASING THROUGH THE DAY AS HEIGHT FALLS SPREAD ACROSS THE AREA.
THIS SHOULD TRANSLATE TO WIDESPREAD COVERAGE OF STORMS BOTH ALONG
THE FRONT AND SHOWERS AND STORMS IN THE COOLER AIR. DEEP LAYER
SHEAR WILL BE STRONG AND THE DEGREE OF SEVERE WEATHER IN THE WARM
SECTOR WILL BE LARGELY DICTICATED BY THE AMOUNT OF INSTABILITY
WHICH WILL BE PRESENT...WHICH IS COMPLICATED BY CLOUD COVER AND
ONGOING STORMS IN THE MORNING. WE WILL ALSO HAVE TO KEEP AN EYE ON
ANY HEAVY RAINFALL POTENTIAL GIVEN THE SLOW MOVEMENT AND HIGH
MOISTURE CONTENT OF THE ATMOSPHERE.
MUCH COOLER CONDITIONS ARE EXPECTED ON THURSDAY WITH EXTENSIVE
CLOUDINESS WITHIN THE CYCLONIC FLOW IN THE WAKE OF THE FRONT. THE
PRESENCE OF A TRAILING VORT MAX AND COLD AIR ALOFT ALSO SUGGESTS A
CHANCE OF INSTABILITY SHOWERS. THE BELOW AVERAGE TEMPERATURES WILL
PERSIST FRIDAY WITH A SLIGHT MODERATION ON SATURDAY. TEMPERATURES
SHOULD WARM TO ABOVE AVERAGE SUNDAY INTO MONDAY AS THE FLOW ALOFT
TRANSITIONS TO QUASI-ZONAL AND SOUTHERLY LOW LEVEL FLOW GETS
UNDERWAY.
GLASS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1218 PM CDT MON APR 8 2013
OUTFLOW BOUNDARY CURRENTLY LOCATED NEAR KUIN WILL REMAIN SOMEWHAT
STATIONARY BEFORE LIFTING NWD LATER THIS AFTERNOON OR EVENING.
KUIN AND KCOU HAVE BEST CHANCES FOR SEEING TSRA THIS AFTERNOON
AND EVENING...BUT CONFIDENCE IS STILL TOO LOW TO PIN DOWN A TIME.
WITH THE BOUNDARY IN THE AREA...CAN NOT RULE OUT THE POSSIBILITY
OF SEEING HIGH END MVFR CIGS AT KUIN PERIODICALLY THIS AFTERNOON.
OTHERWISE...WINDS WILL BACK TO SLY THIS AFTERNOON AND REMAIN SLY
THRU TUES. WINDS SHUD PICK UP TUES WITH GUSTS IN THE 20 KT RANGE.
MUCH BETTER CHANCES EXIST FOR HIGH END MVFR OR LOW VFR CIGS TUES.
LOOKING AT LATEST SAT IMAGE...APPEARS OZARK MNTS ARE BLOCKING
MOISTURE RETURN. EXPECT THAT THIS LOW LVL MOISTURE WILL MOVE NWD
BY TUES...BUT STILL UNCERTAIN HOW FAR N IT WILL BE. WILL LEAVE AS
A SCT DECK FOR NOW.
SPECIFICS FOR KSTL...EXPECT ANY PRECIP TO BE N OF THE TERMINAL
THIS AFTERNOON/EVENING...BUT CAN NOT COMPLETELY RULE OUT THE
POSSIBILITY. WINDS SHUD BACK TO SLY LATE THIS AFTERNOON AND REMAIN
SLY THRU TUES AND INCREASE WITH GUSTS TO AROUND 20 KTS TUES
MORNING.
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1234 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1146 AM CDT MON APR 8 2013
QUICK UPDATE TO TWEAK TEMPS FOR TODAY AND WILL BE UPDATING POPS SOON.
MAIN QUESTION REMAINS WHERE AND WHEN CONVECTION WILL INITIATE. IF
PRECIP DOES OCCUR...BELIEVE THERE WILL BE TWO AREAS. ONE ACROSS
NRN PORTIONS OF THE CWA ALONG AN OUTFLOW BNDY WITH CONVECTION FROM
LAST NIGHT AND THE OTHER ACROSS SRN PORTIONS OF THE CWA. BOTH OF
THESE AREAS HAVE ALREADY HAVE A GOOD CU FIELD.
WITH THE DEEPER CU IN PLACE...SFC BNDY AND STRONGER
CONVERGENCE...BELIEVE THAT THE BOUNDARY ACROSS THE NRN CWA WILL
SEE THE BEST CHANCES FOR PRECIP. WILL BE UPDATING TO INCREASE POPS
ACROSS THIS AREA...BUT WILL LEAVE IN THE CHANCE RANGE FOR NOW.
TILLY
&&
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1218 PM CDT MON APR 8 2013
OUTFLOW BOUNDARY CURRENTLY LOCATED NEAR KUIN WILL REMAIN SOMEWHAT
STATIONARY BEFORE LIFTING NWD LATER THIS AFTERNOON OR EVENING.
KUIN AND KCOU HAVE BEST CHANCES FOR SEEING TSRA THIS AFTERNOON
AND EVENING...BUT CONFIDENCE IS STILL TOO LOW TO PIN DOWN A TIME.
WITH THE BOUNDARY IN THE AREA...CAN NOT RULE OUT THE POSSIBILITY
OF SEEING HIGH END MVFR CIGS AT KUIN PERIODICALLY THIS AFTERNOON.
OTHERWISE...WINDS WILL BACK TO SLY THIS AFTERNOON AND REMAIN SLY
THRU TUES. WINDS SHUD PICK UP TUES WITH GUSTS IN THE 20 KT RANGE.
MUCH BETTER CHANCES EXIST FOR HIGH END MVFR OR LOW VFR CIGS TUES.
LOOKING AT LATEST SAT IMAGE...APPEARS OZARK MNTS ARE BLOCKING
MOISTURE RETURN. EXPECT THAT THIS LOW LVL MOISTURE WILL MOVE NWD
BY TUES...BUT STILL UNCERTAIN HOW FAR N IT WILL BE. WILL LEAVE AS
A SCT DECK FOR NOW.
SPECIFICS FOR KSTL...EXPECT ANY PRECIP TO BE N OF THE TERMINAL
THIS AFTERNOON/EVENING...BUT CAN NOT COMPLETELY RULE OUT THE
POSSIBILITY. WINDS SHUD BACK TO SLY LATE THIS AFTERNOON AND REMAIN
SLY THRU TUES AND INCREASE WITH GUSTS TO AROUND 20 KTS TUES
MORNING.
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1158 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1146 AM CDT MON APR 8 2013
QUICK UPDATE TO TWEAK TEMPS FOR TODAY AND WILL BE UPDATING POPS SOON.
MAIN QUESTION REMAINS WHERE AND WHEN CONVECTION WILL INITIATE. IF
PRECIP DOES OCCUR...BELIEVE THERE WILL BE TWO AREAS. ONE ACROSS
NRN PORTIONS OF THE CWA ALONG AN OUTFLOW BNDY WITH CONVECTION FROM
LAST NIGHT AND THE OTHER ACROSS SRN PORTIONS OF THE CWA. BOTH OF
THESE AREAS HAVE ALREADY HAVE A GOOD CU FIELD.
WITH THE DEEPER CU IN PLACE...SFC BNDY AND STRONGER
CONVERGENCE...BELIEVE THAT THE BOUNDARY ACROSS THE NRN CWA WILL
SEE THE BEST CHANCES FOR PRECIP. WILL BE UPDATING TO INCREASE POPS
ACROSS THIS AREA...BUT WILL LEAVE IN THE CHANCE RANGE FOR NOW.
TILLY
&&
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 601 AM CDT MON APR 8 2013
WARM FRONT HAS MOVED N OF THE TAF SITES LEADING TO S-SWLY SFC
WINDS TODAY AND S-SELY SFC WINDS TGT. ALTHOUGH THERE SHOULD BE SCT-
BKN VFR...LOW LEVEL CLOUDS TODAY AND TGT IT APPEARS THAT THE
MODELS ARE OVERDOING THE LOW LEVEL...BOUNDARY LAYER RH AND ARE
TOO LOW WITH THE CLOUD CEILING FORECAST IN THE MOS GUIDANCE. FOR
NOW WILLL KEEP IT VFR THROUGH THE PERIOD IN THE TAF FORECASTS.
THERE IS ALSO THE POTENTIAL FOR WIDELY SCATTERED SHOWERS OR STORMS
THIS AFTN ACROSS MUCH OF THE AREA...AND SCATTERED SHOWERS AND
STORMS ACROSS NERN MO AND W CNTRL IL TGT. WITH PLENTY OF UNCERTAINTY
WITH TIMING AND LOCATION OF THE CONVECTION WILL LEAVE THE TAFS DRY
FOR NOW.
SPECIFICS FOR KSTL...WITH PLENTY OF LOW LEVEL MOISTURE AND
INSTABILITY THERE WILL BE SCT-BKN DIURNAL CUMULUS CLOUDS THIS
AFTN. MOST OF THIS SHOULD BE VFR. WILL LIKELY HAVE AT LEAST SCT
LOW LEVEL CLOUDS TGT INTO TUE MRNG. THERE MAY BE WIDELY SCATTERED
TO SCATTERED SHOWERS AND STORMS THIS AFTN AND TGT...BUT WILL
LEAVE THE STL TAF DRY FOR NOW WITH NO WELL DEFINED SFC BOUNDARY OR
FORCING MECHANISM TO FOCUS AND INITIATE CONVECTION. S-SWLY SFC
WIND SHOULD CONTINUE TODAY...THEN BECOME MORE S-SELY THIS EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
351 PM MDT MON APR 8 2013
.SHORT TERM...VALID FOR TONIGHT THROUGH TUE NIGHT...
THE THREAT OF HEAVY SNOW ON THE NORTHERN EDGE OF THE FORCING WITH
A DEEP 500-HPA TROUGH LIFTING OUT OF THE FOUR CORNERS REGION INTO
THE HIGH PLAINS THE NEXT 36 HOURS IS THE MAIN FORECAST ISSUE. WE
DECIDED TO AGGRESSIVELY ADVERTISE WARNING CRITERIA SNOW BETWEEN 7
AND 13 INCHES FOR SHERIDAN OVER TO ALBION AND MOORHEAD...AND 5 TO
10 INCHES IN THE AREA JUST NORTH OF THERE EXTENDING INTO SOUTHERN
BIG HORN COUNTY. HOWEVER...WE HAVE TO ADMIT THAT MANY OF THE SAME
QUESTIONS ABOUT THIS EVENT THAT HAVE EXISTED THE LAST COUPLE DAYS
ARE STILL LINGERING...SO THERE IS CERTAINLY A HIGHER-THAN-AVERAGE
POTENTIAL FOR FORECAST ERROR TONIGHT AND TUESDAY.
FIRST OF ALL...THE MORNING BATCH OF SNOW IN SOUTHEASTERN MT WANED
DURING THE EARLY AFTERNOON AS MID-LEVEL FRONTOGENESIS WEAKENED...
AND MOVED INTO NORTH DAKOTA. WE THUS CANCELLED THE ADVISORY A FEW
HOURS EARLY FOR FORSYTH...MILES CITY...AND BAKER BECAUSE THE NEXT
BATCH OF SNOW WILL LARGELY /OR ENTIRELY/ STAY SOUTH OF THERE.
FOR TONIGHT AND TUESDAY...WE ESSENTIALLY SET ASIDE THE 12 UTC GFS
SOLUTION SINCE IT IS A FAST OUTLIER IN TAKING THE DYNAMIC 500-HPA
TROUGH EASTWARD INTO THE PLAINS. THE GFS HAS ALSO BEEN THE DRIEST
SOLUTION IN FAR SOUTHERN MT AND NORTH CENTRAL WY...THOUGH WE NEED
TO NOTE THAT ITS 12 UTC RUN WAS ACTUALLY A BIT WETTER. THE 12 UTC
NAM...ECMWF...09 UTC SREF...AND RECENT RUNS OF THE RAP AGREE WELL
THAT SNOW WILL INTENSIFY BY 06 UTC FROM SHERIDAN TO ABOUT BUFFALO
SOUTH DAKOTA AS 500-300 HPA Q-VECTOR CONVERGENCE CRANKS UP. BASED
ON A BLEND OF THOSE SOLUTIONS...QPF WILL BE BETWEEN 0.40 AND 0.75
INCHES...WITH THE 12 AND 18 UTC NAM SOLUTIONS HEAVIER WITH NEARLY
AN INCH OF LIQUID-EQUIVALENT MOISTURE IN SOME LOCATIONS. ONLY ONE
OF THE 22 NAM-WEIGHTED SREF MEMBERS CALLS FOR STORM TOTAL LIQUID-
EQUIVALENT OF LESS THAN 0.50 INCHES AT SHERIDAN...WITH A MEAN QPF
FROM THE 15 UTC SREF OF 0.80 INCHES. SNOW-TO-LIQUID RATIOS SHOULD
BE IN THE 13 TO 17 TO 1 RANGE BASED ON A BLEND OF TECHNIQUES SUCH
AS THE COBB METHOD. FORECAST SOUNDINGS SUGGEST A PRETTY FAVORABLE
DENDRITIC GROWTH ZONE...WHICH SUPPORTS THOSE HIGHER SNOW RATIOS.
POTENTIAL PROBLEMS WITH THE FORECAST INCLUDE 1/ THE POTENTIAL FOR
SUBTLE CHANGES IN THE TRACK OF THE MID- AND UPPER-LEVEL TROUGH...
AND 2/ THE RISK OF DRIER NORTHERLY LOW-LEVEL AIR WORKING INTO THE
SYSTEM AND REDUCING SNOW TOTALS. DESPITE THOSE POSSIBILITIES...WE
HAD ENOUGH CONFIDENCE TO HOIST A WINTER STORM WARNING FOR THE FAR
SOUTHERN PART OF MONTANA...SHERIDAN COUNTY...AND THE NORTHEASTERN
BIG HORN MOUNTAINS. WE BOUNDED THAT WARNING WITH A WINTER WEATHER
ADVISORY IN SOUTHERN BIG HORN COUNTY...RECOGNIZING THAT ANY SMALL
SHIFTS IN THE NORTHERN EDGE OF THE SNOW FIELD /DETERMINED IN PART
BY THE ADVANCEMENT OR LACK THEREOF OF DRY NORTHERLY FLOW/ WILL BE
THE DRIVING FORCE IN WHERE THE ACTUAL GRADIENT IN HEAVY SNOW ENDS
UP BEING. FINALLY...WE ALSO CAUTIOUSLY ISSUED AN ADVISORY FOR THE
BEARTOOTH AND RED LODGE FOOTHILLS THROUGH 18 UTC TUESDAY BASED ON
A SUBTLE SIGNAL IN EVEN THE COARSER-SCALE GUIDANCE FOR ENOUGH QPF
TO SUPPORT 3 OR MORE INCHES OF UPSLOPE-DRIVEN SNOW THERE.
WE EXPECT SNOWFALL TO WIND DOWN TUESDAY AFTERNOON OR EVENING WHEN
DYNAMICS WANE AND SURFACE RIDGING APPROACHES. LOW TEMPERATURES ON
TUESDAY NIGHT COULD BE EVEN COLDER THAN ADVERTISED IF SUBSTANTIAL
CLEARING OCCURS AND EXPECTED SNOWFALL BECOMES REALITY. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...MON...
SYSTEM CURRENTLY IMPACTING REGION WILL EJECT INTO THE MIDWEST AND
MAKE WAY FOR THE RETURN OF NORTHWESTERLY FLOW BY THE END OF THE
WORK WEEK. A FAIRLY STRONG UPPER LEVEL JET WILL SUBSEQUENTLY KEEP
THINGS MOVING AT A RAPID PACE. MOST OF THE CWA WILL REMAIN ON THE
NORTHERN SIDE OF THE JET WHICH WILL AID IN BRINGING SEVERAL
SHORTWAVES INTO SOUTH CENTRAL MONTANA THROUGH THE EXTENDED PERIOD.
TEMPERATURE FORECAST IS ON TRACK...WITH TEMPERATURES RETURNING TO
MORE NORMAL BY THE END OF THE WEEK.
BY SATURDAY...HOWEVER...ABUNDANT MOISTURE WILL BE AVAILABLE TO
BRING THE POTENTIAL FOR ANOTHER MUCH NEEDED PRECIPITATION EVENT AS
A FRONTAL SYSTEM MAKES ITS WAY ACROSS SOUTH CENTRAL MONTANA BY
SUNDAY AFTERNOON. EC SOLUTION HAS AN UPPER LEVEL LOW FORMING IN
NORTHEAST MONTANA. THIS PREFERRED SOLUTION WOULD BRING THE
AFOREMENTIONED PRECIPITATION EVENT TO MUCH OF SOUTHEASTERN
MONTANA. UPPED POPS TO REFLECT THIS...BUT THE EXACT PERIODS OF
PREFERENCE ARE NOT QUITE CLEAR AT THIS POINT. SINGER
&&
.AVIATION...
BIGGEST IMPACTS FOR AVIATION WILL BE REDUCED VISIBILITIES DUE TO
CONTINUATION OF LATE SEASON WINTER STORM. WIDESPREAD IFR
CONDITIONS WILL PERSIST THROUGH THE EVENING HOURS ESPECIALLY NEAR
KBIL...KMLS AND KBHK...DUE TO OCCASIONAL SNOW AND BLOWING SNOW.
NORTHERLY WINDS MAY GUST TO NEAR 25 KTS MAKING CONDITIONS WORSE AT
TIMES. KSHR WILL SEE POTENTIAL FOR SIGNIFICANT SNOWFALL AND AIR
TRAVEL IMPACTS THROUGH TOMORROW AFTERNOON. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 015/033 017/044 031/054 032/053 031/055 032/053 029/052
+2/S 01/B 33/W 22/W 34/W 33/W 33/W
LVM 015/034 018/052 031/056 030/053 030/053 027/050 025/048
+2/S 01/B 32/W 22/W 34/W 33/W 33/W
HDN 017/032 015/043 027/053 028/053 026/056 029/054 026/052
+3/S 11/B 33/W 22/W 33/W 33/W 33/W
MLS 016/030 016/040 025/048 028/051 026/055 029/054 027/051
21/B 11/U 23/W 22/W 33/W 33/W 33/W
4BQ 010/028 013/036 021/044 024/049 024/053 027/052 024/049
+9/S 31/B 23/W 23/W 23/W 33/W 33/W
BHK 010/026 014/034 019/041 024/046 024/049 024/048 022/045
32/S 11/B 23/W 22/W 24/W 33/W 23/W
SHR 016/027 013/040 022/049 027/049 025/053 027/050 025/049
+9/S 21/B 23/W 23/W 23/W 43/W 44/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT TUESDAY FOR
ZONES 36>38.
WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MDT TUESDAY FOR
ZONES 56-66.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 9 PM MDT TUESDAY FOR
ZONE 58.
WY...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT TUESDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1135 AM MDT MON APR 8 2013
.SHORT TERM...VALID FOR TDY AND TUE...
WE WILL LET THE WINTER WEATHER ADVISORY FOR HARLOWTON...JUDITH GAP
AND ROUNDUP EXPIRE AS PLANNED AT 18 UTC. LIGHT SNOW CONTINUES OVER
THOSE AREAS...BUT SIGNIFICANT ACCUMULATIONS ARE OVER WITH AND ROAD
CONDITIONS ARE SLOWLY IMPROVING. THE REST OF THE ADVISORY AT MILES
CITY AND BAKER WILL REMAIN IN TACT FOR NOW.
AS LONG AS WE ARE UPDATING THE FORECAST...WE WILL INCREASE POPS IN
MOST PLACES TO 100 PERCENT FOR THE REST OF THE DAY BASED ON TRENDS
IN RADAR AND OBSERVATIONAL DATA AS OF 1730 UTC. SCHULTZ
PREVIOUS DISCUSSION...ISSUED AT 934 AM MDT MON APR 8 2013...
FRONTOGENETICALLY-INDUCED SNOW CONTINUES ITS TREK ACROSS SOUTHEAST
MT THIS MORNING...WITH VISIBILITY DOWN TO 1/4SM AT BAKER AT TIMES.
REPORTS IN THE WAKE OF THIS BAND OVERNIGHT WERE GENERALLY IN THE 3
TO 5 INCH RANGE FROM NEAR HARLOWTON TO ROUNDUP...FORSYTH AND MILES
CITY. THE 12 UTC NAM AND RECENT RAP RUNS SHOW THE FRONTOGENESIS IN
THE 850-700 HPA LAYER OVER SOUTHEASTERN MT WILL WEAKEN BY ABOUT 18
UTC AS THE BETTER FORCING SHIFTS INTO NORTH DAKOTA. THIS IDEA FITS
UPSTREAM TRENDS WELL WITH IMPROVING VISIBILITIES AT MILES CITY. IT
LOOKS LIKE WE WILL BE ABLE TO LET THE HARLOWTON AND JUDITH GAP TO
ROUNDUP PART OF THE WINTER WEATHER ADVISORY EXPIRE AS SCHEDULED AT
18 UTC. THE MILES CITY TO BAKER PART OF IT MIGHT BE DROPPED DURING
THE MID AFTERNOON...BUT GIVEN WEAK UPSLOPE SOME LIGHT SNOW WILL BE
GOING ON EVEN BEHIND THE MAIN BAND...SO WE PLAN TO BE SLOW TO DROP
THE HEADLINES GIVEN CONTINUED SLIPPERY ROADS.
ONLY MINOR CHANGES WERE MADE TO THE FORECAST WITH THIS UPDATE. THE
POPS AROUND SHERIDAN WERE REDUCED THIS MORNING BECAUSE THE FORCING
TIED TO THE EVOLVING 500-HPA TROUGH IN THE CENTRAL ROCKIES DOESN/T
LOOK TO REACH THERE UNTIL CLOSER TO 21 UTC. OTHERWISE...ONLY A FEW
OBSERVATIONALLY-BASED ADJUSTMENTS WERE MADE TO TODAY/S FORECAST AT
THIS POINT...INCLUDING LOWERING HIGHS A FEW DEGREES IN MOST SPOTS.
OUR MAIN FOCUS HEADING FORWARD WILL BE ON DETERMINING THE NORTHERN
EXTENT OF HEAVY SNOW TONIGHT AND TUESDAY...WITH POTENTIAL FOR 6 OR
MORE INCHES FROM SHERIDAN TO MOORHEAD AND ALBION. THE QPF FROM THE
12 UTC NAM STRONGLY SUPPORTS UPGRADING OUR WINTER STORM WATCH TO A
WARNING. HOWEVER...WE WILL TAKE A LOOK AT THE REMAINDER OF THE NEW
MORNING GUIDANCE BEFORE MAKING A DECISION ON HEADLINES TONIGHT AND
TUESDAY BY THE EARLY TO MID AFTERNOON. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
DRY WEDNESDAY WITH MODERATION IN TEMPERATURES WILL BE FOLLOWED BY
A PACIFIC FRONT OVERNIGHT WHICH WILL BRING A PREVALENT NORTHWEST
FLOW ON THURSDAY AND FRIDAY. BY SATURDAY THE FLOW BEGINS TO BACK
AS AN UPPER LOW OVER THE GULF OF ALASKA TRACKS SOUTHWARD ALONG THE
BC COAST. THIS PUSHES ANOTHER COLD FRONT THROUGH THE REGION
DURING THE WEEKEND. JET STREAM REMAINS SOUTH OF THE REGION FOR
EARLY NEXT WEEK WITH TEMPERATURES BELOW NORMAL.
BEST CHANCES FOR PRECIPITATON WILL BE WITH THE WEDNESDAY NIGHT
FRONT AND THEN AS THE FLOW BACKS DURING THE WEEKEND IN RESPONSE TO
THE BC LOW. NO PARTICULAR PERIOD LOOKS IMPRESSIVE AT THIS POINT
FOR SIGNIFICANT WIDESPREAD BUT UNSETTLED WEATHER SHOULD BE
EXPECTED AFTER WEDNESDAY. TEMPERATURES WILL REMAIN NEAR NORMAL
THURSDAY THROUGH SATURDAY BEFORE FALLING SUNDAY. BORSUM
&&
.AVIATION...
LATE SEASON WINTER STORM CONTINUES TO MOVE ACROSS CENTRAL AND
EASTERN MONTANA THIS MORNING. WIDESPREAD IFR CONDITIONS WILL
PERSIST THROUGH THE MORNING HOURS ESPECIALLY NEAR KMLS AND
KBHK...DUE TO SNOW AND FOGGY CONDITIONS. NORTHERLY WINDS MAY PICK
UP BY THIS AFTERNOON NEAR KMLS AND KBHK MAKING CONDITIONS WORSE AT
TIMES. SNOWFALL MAY INCREASE AT ALL TERMINALS AGAIN THIS AFTERNOON
AS WELL. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 028 015/036 019/045 030/056 034/053 032/053 030/052
+/S 31/B 01/B 33/W 22/W 33/W 33/W
LVM 030 015/037 021/049 030/053 030/051 029/050 027/049
+/S 41/B 01/B 32/W 22/W 33/W 33/W
HDN 030 017/035 015/045 026/057 029/054 027/054 027/054
9/S 41/B 11/B 33/W 22/W 33/W 33/W
MLS 029 016/032 016/041 023/052 028/052 028/052 026/052
+/S 21/B 11/B 23/W 22/W 33/W 32/W
4BQ 032 010/031 011/039 019/052 025/051 026/051 025/051
7/S 87/S 31/B 23/W 23/W 23/W 33/W
BHK 029 010/028 013/036 017/045 028/046 026/046 022/046
+/S 42/S 11/B 23/W 22/W 23/W 32/W
SHR 031 016/031 015/040 021/054 028/051 027/052 025/051
8/S 87/S 21/B 23/W 23/W 23/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MDT THIS
EVENING FOR ZONES 31>33.
WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONES 36-37.
WY...WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
322 PM CDT MON APR 8 2013
.SHORT TERM...TONIGHT THROUGH THURSDAY
STRONG SPRING STORM SYSTEM IS KNOCKING AT OUR DOOR...WITH ACTIVE
WEATHER EXPECTED FOR THE NEXT FEW DAYS. SUBJECTIVE 12Z UPPER AIR
ANALYSIS INDICATES UPPER-LEVEL TROUGH DEEPENING INTO A LOW OVER
THE GREAT BASIN...WITH 500MB HEIGHT FALLS UP TO 150M. ANOTHER
SHORTWAVE WAS ADVANCING ACROSS IA...WITH 70M HEIGHT FALLS
ASSOCIATED WITH IT. UPPER-LEVEL JET WAS STRONGEST ON THE BACK SIDE
OF THE DIGGING UPPER LOW..WITH UP TO 110KT ALONG THE PACIFIC
COAST. MOISTURE AXIS AT 850MB EXTENDED FROM TX THROUGH EASTERN
KS/WESTERN MO AS FAR NORTH AS THE NEB AND IA BORDERS...WTIH A
DEVELOPING LEE LOW IN SOUTEAST CO/OK PANDHANDLE/SOUTHWEST KS. SUB-
0C TEMPS AT 850MB EXTENDED FROM MT THROUGH ND INTO NORTHERNMOST
MN. RAP ANALYSIS AT 19Z INDICATED A SURFACE LOW IN SOUTHEAST
CO/NORTHEAST NM...WITH FRONTAL BOUNDARY EXTENDING FROM SOUTHWEST
NEB THROUGH NORTHEAST NEB AS COLD AIR BEGINS TO DESCEND OUT OF SD
WHILE WARM AIR ADVECTION CONTINUES AHEAD OF THE LOW.
MAIN FORECAST CONCERNS INCLUDE CONVECTIVE POTENTIAL THIS EVENING AND
TONIGHT AND IN THE SOUTHERN CWA THROUGH TUESDAY...AS WELL AS WINTER
WEATHER POTENTIAL IN THE NORTHWEST CWA EARLY TUESDAY MORNING THROUGH
WEDNESDAY. LINGERING CLOUDS ARE INHIBITING WARMING IN THE
SOUTH...WHICH MIGHT MAKE REACHING CONVECTIVE TEMPERATURE A
CHALLENGE. STORMS ARE LIKELY TO FIRE THIS AFTERNOON FURTHER WEST IN
KS...AND MOVE ACROSS NORTHERN KS/SOUTHERN NEB LATER THIS EVENING
THROUGH TONIGHT. MEANWHILE...COLD FRONT DESCENDING OUT OF SD IS
LIKELY TO REACH THE NORTHERN CWA THIS EVENING/TONIGHT...AND SHOULD
BEGIN TO SEE RAIN ALONG THAT FRONT AS WELL. HAVE INCLUDED THUNDER
MENTION EVERYWHERE THIS EVENING...BUT STARTED TO TAKE IT OUT OF THE
NORTHERN CWA AFTER MIDNIGHT. DOES APPEAR THAT SURFACE TEMPS WILL
REMAIN ABOVE FREEZING THROUGH THE NIGHT ACROSS THE AREA...AND THUS
HAVE INDICATED RAIN...BUT SHOULD COLD AIR ARRIVE FASTER THAN
FORECAST...MAY SEE A CHANGE TO WINTRY MIX A LITTLE EARLIER.
COLD AIR ADVECTION WILL CONTINUE TUESDAY IN THE NORTHERN CWA AS
FRONT SLOWLY DIGS THROUGH THE CWA. NORTHWESTERN CWA SHOULD FALL
BELOW FREEZING NEAR THE GROUND BY MID-MORNING TUESDAY...AND WITH
LINGERING MID-LEVEL WARM NOSE...WOULD EXPECT PRECIPITATION TO CHANGE
FROM RAIN TO FREEZING RAIN/SLEET. SOUNDINGS ARE ON THE FENCE ON
WHICH WAY TO GO WITH PRECIP TYPE...AND HAVE INCLUDED A MIX OF BOTH.
OBVIOUSLY...IF ONE PHASE DOMINATES...IMPACTS WILL BE SIGNIFICANTLY
DIFFERENT. DID MOVE BACK TIMING ON WINTER STORM WATCH TO BEGIN AT
12Z IN THE FAR NORTHWEST AND 15Z IN THE REMAINING COUNTIES...BUT
WILL LET THE NEXT SHIFT MAKE AN ASSESSMENT ON TEMPERATURE PROFILES
TO DETERMINE POSSIBLE CONVERSION TO WARNING OR ADVISORY. FURTHER
SOUTH...HAVE INCLUDED THUNDERSTORM MENTION IN THE SOUTHEASTERN CWA
AS FRONT IS LIKELY TO ARRIVE DURING THE AFTERNOON WHEN SOME
DESTABILIZATION HAS OCCURRED.
FOLLOWED MODEL SOUNDINGS PRETTY CLOSELY FOR PRECIP TYPE THROUGH
TUESDAY NIGHT...WITH MORE OF A NAM/SREF FLAVOR LEANING TOWARD
CONTINUED ZR/IP. GFS DID LEAN MORE TOWARD SNOW...BUT FOR NOW...HAVE
LEANED TO THE WARMER MID-LEVEL SOLUTION AS THE SLOW-MOVING SYSTEM
CONTINUES TO ALLOW MID-LEVEL WARM AIR ADVECTION AND TROWALING AHEAD
OF IT. MOST OF THE EASTERN HALF OF THE CWA IS PROGGED TO REMAIN
RAIN THROUGH WEDNESDAY...WHILE PRECIPITATION TRANSITIONS TO A MIX
WITH SNOW IN THE NORTHWEST CWA. DELAYED TRANSITION SHOULD HOLD DOWN
AMOUNTS FOR ANY FROZEN PRECIPITATION ACROSS MOST OF THE CWA...AS
PRECIP AMOUNTS ARE PROGGED TO DIMINISH QUITE A BIT ON WEDNESDAY
NIGHT BY THE TIME TEMPS ARE COLD ENOUGH TO ALLOW SNOW ACROSS THE
REST OF THE CWA. STILL...AS WITH ALL PRECIP TYPE ISSUES...THE LINE
BETWEEN PRECIP TYPES IS THIN...AND CONFIDENCE IS ALWAYS ON THE LOW
SIDE FOR THESE TRANSITIONS. AN EARLIER CHANGEOVER WITH COLDER MID-
LEVELS WOULD PRODUCE MORE SNOW ACROSS THE AREA. PRECIPITATION
SHOULD FINALLY BEGIN TO EXIT THE AREA BY THURSDAY...BUT DID LOWER
TEMPS BY SEVERAL DEGREES ON THURSDAY AS THE COLDEST 850MB TEMPS PASS
OVER THE AREA.
MAYES
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
TEMPERATURES SHOULD BEGIN A MODERATING TREND THROUGH LATE WEEK
AND INTO THE WEEKEND AS UPPER-LEVEL FLOW RETURNS TO ZONAL...WITH
TEMPERATURES RETURNING TO NEAR-NORMAL READINGS FOR THE WEEKEND.
MODEL BLENDS CONTINUE TO GIVE A SLIGHT CHANCE TO SMALL CHANCE OF
PRECIPITATION ON SATURDAY NIGHT THROUGH MONDAYNIGHT...BUT
CONFIDENCE IS VERY LOW AS MODELS CONTINUE TO EXHIBIT SIGNIFICANT
RUN TO RUN VARIABILITY IN THE TIMING OR LOCATION OF ANY RAIN.
PRECIPITATION WOULD NOT BE LIKELY DURING ALL OF THOSE
PERIODS...BUT RATHER OVER A NARROWER WINDOW BETWEEN SATURDAY NIGHT
AND MONDAY NIGHT.
MAYES/BOUSTEAD
&&
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
IFR CONDITIONS WILL CONTINUE FOR ANOTHER HOUR OR TWO AT OMA/LNK
BEFORE THINGS START TO SCATTER OUT A BIT AND VISBY IMPROVES TO
VFR. VFR CONDITIONS WILL CONT THROUGH THE AFTN AT OFK. A WARM
FRONT WILL MOVE NORTH TODAY TOWARD THE OMA/LNK TAF SITES AND THIS
MAY BE A FOCUS FOR SOME LATE AFTN AND EVENING THUNDERSTORMS. DUE
TO TIMING AND CAP UNCERTAINTIES WE WILL NOT INCLUDE THUNDER IN THE
TAFS YET THIS EVENING...BUT THIS MAY BE NEEDED LATER. WE WILL
INCLUDE SHOWERS OVERNIGHT AT ALL 3 SITES THOUGH AS ACTIVITY TO
THE WEST SPREAD EASTWARD. WIDESPREAD IFR/LIFR CONDITIONS WILL
RETURN TONIGHT AS STRATUS DEVELOPS AS SOUTHERLY FLOW AGAIN
INCREASES. THE IFR CIGS SHOULD CONT THROUGH THE REST OF THIS TAF
PERIOD AT ALL SITES. MVFR VISBY IS ALSO LIKELY TO DEVELOP TOWARD
06Z AND CONT THROUGH THE REST OF THE TAF PERIOD.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ012-017-030-031.
WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ011-016.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
313 PM CDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
DEEP CONVECTION SHOULD DEVELOP WEST TO EAST TONIGHT WITH LARGE HAIL
THE PRIMARY SEVERE WEATHER THREAT. THERE IS A NARROW WINDOW FOR
TORNADOES ASSOCIATED WITH A SOUTHWARD MOVING COLD FRONT THIS EVENING
AND STORMS DEVELOPING ALONG OR JUST SOUTH OF THE FRONT. THE
THUNDERSTORMS WILL HELP PULL COLD AIR SOUTH WHICH COULD CAUSE A
CHANGEOVER TO FREEZING RAIN FASTER THAN FORECAST.
THE RAP HAS WEAKENED THE MIDLEVEL WARM AIR ADVECTION SUFFICIENTLY TO
REDUCE THE RISK OF SLEET HOWEVER THIS WOULD SUGGEST MORE FREEZING
RAIN OR FREEZING DRIZZLE POTENTIAL TUESDAY AS THE MOISTURE IS
GENERALLY BELOW 700 MB IN ALL MODELS. THE LATEST FORECAST SHOWS LESS
QPF TUESDAY BUT SOME AREAS COULD SEE BETWEEN 1/4 AND 1/2 INCH OF
FREEZING RAIN AS THE CHANGEOVER LINE WILL SPEND MOST OF THE DAY
HOURS TRAVERSING EASTERN PORTIONS OF THE FCST AREA.
THE SNOW LINE IS A LITTLE FASTER IN THE RAP BUT THE RAIN TO FREEZING
RAIN LINE SHOULD BE DRAPED ACROSS CUSTER AND FRONTIER COUNTY BY 12Z
TUESDAY. ALL OF THIS SUGGESTS THE COLD AIR IS WINNING OUT IN THE
WEST AND TAKING A MORE NORTH TO SOUTH PLUNGE. THERE NO REAL CHANGE
IN THE SNOWFALL AMOUNTS DURING THE SHORT TERM EXCEPT HIGHER AMOUNTS
ASSOCIATED WITH THE SLIGHTLY FASTER CHANGEOVER IN THE WEST.
ICING COULD BE A REAL PROBLEM FOR THE POWER GRID IN SOME AREAS WITH
WINDS INCREASING TO 25 TO 35 MPH. TEMPERATURES SHOULD BE STEADY OR
FALLING IN THE 20S THROUGHOUT THE DAY AND WIND CHILL READINGS IN THE
SINGLE DIGITS ARE EXPECTED ALL AREAS BY TUESDAY NIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
EARLY TUESDAY EVENING THE H5 UPPER LOW IS FORECAST TO ROTATE INTO
CENTRAL COLORADO WHILE THE H7 LOW MOVES INTO FAR NORTHEAST CO/SWRN
NEBR/NWRN KS. THIS WILL BE CONDUCIVE FOR A PERIOD OF MODERATE TO
HEAVY SNOW IS TO DEVELOP IN NW KS AND DRAWN NORTHWARD INTO
WESTERN NEBRASKA. NORTHWEST WINDS 25 TO 35 MPH AND GUSTY TO
PRODUCE AREAS OF BLOWING SNOW TO DIMINISH SLIGHTLY TO 20 TO 30
MPH AFTER MIDNIGHT. THE SYSTEM WILL BEGIN TO WEAKEN AS DRIER AIR
IS DRAWN INTO THE EASTERN SIDE OF THE SYSTEM. A PERSISTENT
DEFORMATION ZONE ON THE BACKSIDE OF THE SYSTEM WILL STILL BRING
LIGHT SNOW ACCUMULATIONS LATE TUESDAY NIGHT THROUGH WEDNESDAY.
EVEN WEDNESDAY NIGHT INTO THURSDAY...THE NORTHEAST HALF OF THE
AREA MAY CONTINUE TO SEE LIGHT SNOW AS UPPER LOW ROTATES SLOWLY
EAST INTO IOWA.
HAVE TRENDED DOWN HIGH TEMPERATURES WEDNESDAY TO THE UPPER 20S AND
LOWER 30S. THURSDAY HIGHS ALSO TRENDED DOWN A BIT TO 33 TO 35
NORTH CENTRAL TO THE LOWER 40S FAR SOUTHWEST.
IN WAKE OF CLOSED SYSTEM THURSDAY...UPPER FLOW WILL BE WEST
NORTHWEST FRIDAY THROUGH MONDAY. TEMPERATURES TO MODERATE FROM
40 TO 50 FRIDAY TO THE 50S TO LOW/MID 60S SATURDAY AND SUNDAY. LOW
CHANCE POPS SUNDAY/MONDAY FOR RAIN SHOWERS...NIGHTTIME/MORNING
RAIN/SNOW SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1251 CDT MON APR 8 2013
WINTER STORM CONDITIONS WITH WIDESPREAD IFR/LIFR SPREAD SOUTH AND
EAST THIS AFTERNOON THROUGH NOON TUESDAY. FLIGHT CONDITIONS
SLOWLY DETERIORATE FROM NORTH TO SOUTH THIS AFTERNOON AS STRATUS
DEVELOPS. THUNDERSTORM POTENTIAL BECOMES LIKELY ALONG INTERSTATE
80 AFTER 00Z THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 AM CDT /3 AM MDT/ TUESDAY TO 7 AM
CDT /6 AM MDT/ WEDNESDAY FOR NEZ029-038-058-069>071.
WINTER STORM WARNING FROM 4 AM CDT /3 AM MDT/ TUESDAY TO 7 AM
CDT /6 AM MDT/ WEDNESDAY FOR NEZ006>010-024>028-035>037-056-057-
059.
WINTER STORM WARNING FROM 1 AM CDT /MIDNIGHT MDT/ TUESDAY TO 7
AM CDT /6 AM MDT/ WEDNESDAY FOR NEZ004-005-022-023-094.
&&
$$
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1215 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1207 PM CDT MON APR 8 2013
OTHER THAN THE FREEZING RAIN AND DRIZZLE ENDING NORTH DUE TO THE
PRESENCE OF ICE CRYSTALS ALOFT...THE CURRENT HEADLINES AREAS LOOK
GOOD FOR THE AFTERNOON. BOWMAN RADAR DOES SHOW THE BEGINNING OF
THE BACK EDGE OF MODERATE TO HEAVY SNOW. THIS SUGGESTS THE PERIOD
OF VERY HEAVY SNOW ACROSS THE SOUTHWEST MAY TRANSITION TO
CONTINUOUS LIGHT TO OCCASIONAL MODERATE SNOW...WITH MUCH OF THE
ACCUMULATIONS FALLING BY 7 PM. WILL KEEP THE HEADLINES GONG
THROUGH MIDNIGHT FOR RESIDUAL SNOW DURING THE EVENING.
UPDATE ISSUED AT 944 AM CDT MON APR 8 2013
UPGRADING TO WINTER STORM WARNING FOR HEAVY SNOW SOUTHWEST
COUNTIES OF GOLDEN VALLEY...BILLINGS...STARK...DUNN...HETTINGER
MCKENZIE...SLOPE. RADAR ANS SURFACE REPORTS SHOW BAND OF HEAVY
SNOW WILL EXTEND ACROSS THE SOUTHWEST. MOST OF THE HEAVY SNOW WILL
FALL THROUGH EARLY AFTERNOON THEN BEGIN TO DIMINISH.
UPDATE ISSUED AT 650 AM CDT MON APR 8 2013
SURFACE OBSERVATIONS AT STANLEY...MINOT AIR FORCE BASE AND BELCOURT
ARE INDICATING FREEZING RAIN. ALSO A REPORT OF FREEZING RAIN AND
SLEET AT LANSFORD. FORECAST SOUNDINGS INDICATE THIS SHOULD BE A
SHORT LIVED EVENT...WITH COLUMN CONTINUING TO COOL. THERE WAS ALSO
RAIN LAST NIGHT THAT HAS NOW FROZEN TO SURFACES. WILL ISSUE A
FREEZING RAIN ADVISORY TO COVER THE ICY CONDITIONS THROUGH THE
MORNING COMMUTE. WILL GO THROUGH NOON AND LET THE DAY SHIFT CANCEL
IF NEEDED.
SNOW CONTINUES TO LIFT NORTH AND EAST THROUGH SOUTHWEST NORTH
DAKOTA. NO CHANGES TO THE SNOW AND BLOWING SNOW ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 944 AM CDT MON APR 8 2013
WIDESPREAD IFR CONDITIONS ACROSS SOUTHWEST NORTH DAKOTA THROUGH 00Z.
HEAVY SNOW AND BLOWING SNOW KDIK. LIGHT SNOW KISN-KMOT-KDIK-KJMS
WITH IFR KBIS-KJMS. CONDITIONS IMPROVING TO MVFR TO VFR KISN-
KMOT LATE AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ009-019-020-034-042>044.
WINTER STORM WARNING UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY FOR
NDZ017-018-031>033-040-041.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
703 PM EDT MON APR 8 2013
.SYNOPSIS...
A NEARLY STATIONARY FRONTAL BOUNDARY WILL LINGER OVER NORTHERN
OHIO THROUGH MID WEEK...KEEPING MILD AND UNSETTLED WEATHER IN THE
FORECAST. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED
THURSDAY WHEN A STRONG COLD FRONT IS FORECAST TO CROSS THE AREA.
COOLER AIR WILL ARRIVE FRIDAY AFTER THE FRONT MOVES EAST.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW PRESSURE IS CENTERED OVER LAKE MICHIGAN...WITH A WARM FRONT
EXTENDING TO NORTHEAST OHIO. ILN AREA IS IN THE WARM SECTOR...WITH
MOSTLY CLOUDY SKIES AND A BREEZY AND MILD SOUTHERLY FLOW.
THE LOW WILL MOVE EAST TONIGHT ACROSS THE STATE OF MICHIGAN INTO
SOUTHERN ONTARIO. IN THE PROCESS...A BOUNDARY IS FORECAST TO SET
UP IN COUNTIES NORTH OF DAYTON. RAP MODEL LOOKS TO HAVE THE BEST
REPRESENTATION OF THE BOUNDARY...WITH THE LOWER RESOLUTION GFS AND
ECMWF ALSO SUGGESTING SUCH A SOLUTION. THE NAM APPEARS TO BE THE
OUTLIER IN SHOWING A BOUNDARY DEVELOPING FARTHER SOUTH OVER
KENTUCKY. AN AREA OF INSTABILITY MOVING FROM INDIANA MAY COME
INTO PLAY WHEN THE BOUNDARY DEVELOPS THIS EVENING.
WENT WITH A CHANCE OF A SHOWERS WITH A SLIGHT CHANCE FOR
THUNDERSTORMS THIS EVENING IN NORTHERN COUNTIES AFFECTED BY THE
BOUNDARY...DIMINISHING TO A SLIGHT CHANCE OF SHOWERS LATER
TONIGHT.
LOWS WILL BE ABOVE NORMAL IN THE MID 50S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
FOR TUESDAY THROUGH WEDNESDAY...THE BOUNDARY WILL STAY POSITIONED
OVER NORTHERN OHIO. THIS WILL KEEP THE ILN IN A WARM SOUTHERLY
FLOW. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP IN THE
UNSTABLE AIRMASS MAINLY NORTH OF I-70...CLOSER TO THE FRONTAL
BOUNDARY AND ITS ASSOCIATED SHORT WAVE ENERGY AND DEEPER MOISTURE.
MAIN ELEMENT OF INTEREST MAY BE HIGH TEMPERATURES REACHING WELL INTO
THE 70S...WITH LOWER 80S CREEPING INTO SOME SOUTHERN LOCATIONS ON
WEDNESDAY. NORMAL HIGHS RANGE FROM THE UPPER 50S TO LOWER 60S.
FOR WEDNESDAY NIGHT...LOW PRESSURE FORMING TO THE WEST WILL PUSH A
STRONG COLD FRONT TOWARD THE AREA. SHOWERS AND THUNDERSTORMS WILL
BECOME LIKELY OVER WESTERN LOCATIONS LATE WEDNESDAY NIGHT. CANNOT
RULE OUT SEVERE THUNDERSTORMS IN A HIGH SHEAR LOW INSTABILITY
ENVIRONMENT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
POTENT SHORT WAVE WILL LIFT ACROSS THE REGION AT THE BEGINNING OF
THE PERIOD. THIS WILL PUSH A STRONG COLD FRONT THROUGH THE REGION
THURSDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AHEAD
OF THIS BOUNDARY. SHEAR WILL BE SUFFICIENT FOR SEVERE THUNDERSTORMS
BUT INSTABILITY IS IN QUESTION.
ACTIVITY WILL MOVE EAST OF THE REGION THURSDAY NIGHT. BUT THERE IS
THE POTENTIAL FOR ADDITIONAL SHOWERS ON FRIDAY WITH A SECONDARY
TROUGH SWINGING THROUGH. HIGH PRESSURE WILL BUILD IN FOR THE
WEEKEND. TEMPERATURES WILL DROP BACK BELOW NORMAL AT THE END OF THE
WEEK BUT THEN START TO MODERATE. MODELS SHOWING TIMING DISCREPANCIES
WITH A COLD FRONT THAT COULD POTENTIALLY IMPACT MONDAY. SEEMS MORE
LIKELY THAT THE FRONT WILL STAY FAR ENOUGH WEST THROUGH THE END OF
THE PERIOD THAT FURTHER RAIN CHANCES WILL BE QUITE LIMITED.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A STATIONARY FRONTAL BOUNDARY ACROSS THE SOUTHERN GREAT LAKES THIS
EVENING WILL REMAIN QUASI-STATIONARY THROUGH THE TAF PERIOD.
IN THE SHORT TERM...FAVORABLE AXIS OF INSTABILITY IN ASSOCIATION
WITH LOW LEVEL CONVERGENCE WAS LOCATED FROM NORTHERN
ILLINOIS...NORTHERN INDIANA...INTO NORTHWEST OHIO. MOSAIC RADAR
HAS BEEN SHOWING SHOWER DEVELOPMENT HERE. HIGH RESOLUTION MODELS
SUGGEST THAT THESE SHOWERS...AND PERHAPS A THUNDERSTORM...WILL
DRIFT EAST/SOUTHEAST TOWARD THE TAF SITES OF KKDAY...KCMH...KLCK
THROUGH 04Z. THEREAFTER...LOW LEVEL FORCING WITH THIS PCPN
WEAKENS. AS A RESULT...WILL PLACE A TEMPO PERIOD OF LIGHT SHOWERS
AT THE AFOREMENTIONED TAF SITES WITH ONLY A VCSH POSSIBLE ELSEWHERE.
FOR THE OVERNIGHT PERIOD INTO THE FIRST PART OF TUESDAY...ANOTHER
EMBEDDED MID LEVEL WEATHER DISTURBANCE AND ASSOCIATED 850 MB JET
MAY GENERATE ANOTHER AREA OF SHOWERS AND THUNDERSTORMS TO OUR
WEST/NORTHWEST ACROSS NORTHERN/CENTRAL ILLINOIS AND INDIANA LATE.
IT IS UNCLEAR HOW MUCH OF THIS ACTIVITY MAY DRIFT INTO NORTHWEST
AND WEST CENTRAL OHIO TOWARD MORNING. DUE TO LOW CONFIDENCE...HAVE
KEPT A VCSH AT KDAY. BY MID MORNING INTO MID AFTERNOON...POTENTIAL
PCPN NEAR KDAY WILL SHIFT EAST/NORTHEAST...AND WITH DAYTIME
MIXING...TAF SITES SHOULD BE FIRMLY IN THE WARM SECTOR WITH LITTLE
CHANCES OF SHOWERS AND THUNDERSTORMS EXPECTED WITH A NOTICEABLE
MID LEVEL CAPPING INVERSION.
WINDS WILL BECOMING VARIABLE OVERNIGHT NEAR KDAY...KCMH..KLCK WITH
LIGHT SOUTHERLY ELSEWHERE. DAYTIME MIXING ON TUESDAY WILL INCREASE
WINDS FROM THE SOUTH AROUND 15 KNOTS WITH GUSTS OF 25 KNOTS
POSSIBLE DURING THE PEAK HEATING HOURS OF THE DAY.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY INTO WEDNESDAY NIGHT.
THUNDERSTORMS LIKELY THURSDAY INTO THURSDAY EVENING. MVFR
CEILINGS POSSIBLE THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
435 PM EDT MON APR 8 2013
.SYNOPSIS...
A NEARLY STATIONARY FRONTAL BOUNDARY WILL LINGER OVER NORTHERN
OHIO THROUGH MID WEEK...KEEPING MILD AND UNSETTLED WEATHER IN THE
FORECAST. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED
THURSDAY WHEN A STRONG COLD FRONT IS FORECAST TO CROSS THE AREA.
COOLER AIR WILL ARRIVE FRIDAY AFTER THE FRONT MOVES EAST.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW PRESSURE IS CENTERED OVER LAKE MICHIGAN...WITH A WARM FRONT
EXTENDING TO NORTHEAST OHIO. ILN AREA IS IN THE WARM SECTOR...WITH
MOSTLY CLOUDY SKIES AND A BREEZY AND MILD SOUTHERLY FLOW.
THE LOW WILL MOVE EAST TONIGHT ACROSS THE STATE OF MICHIGAN INTO
SOUTHERN ONTARIO. IN THE PROCESS...A BOUNDARY IS FORECAST TO SET
UP IN COUNTIES NORTH OF DAYTON. RAP MODEL LOOKS TO HAVE THE BEST
REPRESENTATION OF THE BOUNDARY...WITH THE LOWER RESOLUTION GFS AND
ECMWF ALSO SUGGESTING SUCH A SOLUTION. THE NAM APPEARS TO BE THE
OUTLIER IN SHOWING A BOUNDARY DEVELOPING FARTHER SOUTH OVER
KENTUCKY. AN AREA OF INSTABILITY MOVING FROM INDIANA MAY COME
INTO PLAY WHEN THE BOUNDARY DEVELOPS THIS EVENING.
WENT WITH A CHANCE OF A SHOWERS WITH A SLIGHT CHANCE FOR
THUNDERSTORMS THIS EVENING IN NORTHERN COUNTIES AFFECTED BY THE
BOUNDARY...DIMINISHING TO A SLIGHT CHANCE OF SHOWERS LATER
TONIGHT.
LOWS WILL BE ABOVE NORMAL IN THE MID 50S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
FOR TUESDAY THROUGH WEDNESDAY...THE BOUNDARY WILL STAY POSITIONED
OVER NORTHERN OHIO. THIS WILL KEEP THE ILN IN A WARM SOUTHERLY
FLOW. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP IN THE
UNSTABLE AIRMASS MAINLY NORTH OF I-70...CLOSER TO THE FRONTAL
BOUNDARY AND ITS ASSOCIATED SHORT WAVE ENERGY AND DEEPER MOISTURE.
MAIN ELEMENT OF INTEREST MAY BE HIGH TEMPERATURES REACHING WELL INTO
THE 70S...WITH LOWER 80S CREEPING INTO SOME SOUTHERN LOCATIONS ON
WEDNESDAY. NORMAL HIGHS RANGE FROM THE UPPER 50S TO LOWER 60S.
FOR WEDNESDAY NIGHT...LOW PRESSURE FORMING TO THE WEST WILL PUSH A
STRONG COLD FRONT TOWARD THE AREA. SHOWERS AND THUNDERSTORMS WILL
BECOME LIKELY OVER WESTERN LOCATIONS LATE WEDNESDAY NIGHT. CANNOT
RULE OUT SEVERE THUNDERSTORMS IN A HIGH SHEAR LOW INSTABILITY
ENVIRONMENT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
POTENT SHORT WAVE WILL LIFT ACROSS THE REGION AT THE BEGINNING OF
THE PERIOD. THIS WILL PUSH A STRONG COLD FRONT THROUGH THE REGION
THURSDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AHEAD
OF THIS BOUNDARY. SHEAR WILL BE SUFFICIENT FOR SEVERE THUNDERSTORMS
BUT INSTABILITY IS IN QUESTION.
ACTIVITY WILL MOVE EAST OF THE REGION THURSDAY NIGHT. BUT THERE IS
THE POTENTIAL FOR ADDITIONAL SHOWERS ON FRIDAY WITH A SECONDARY
TROUGH SWINGING THROUGH. HIGH PRESSURE WILL BUILD IN FOR THE
WEEKEND. TEMPERATURES WILL DROP BACK BELOW NORMAL AT THE END OF THE
WEEK BUT THEN START TO MODERATE. MODELS SHOWING TIMING DISCREPANCIES
WITH A COLD FRONT THAT COULD POTENTIALLY IMPACT MONDAY. SEEMS MORE
LIKELY THAT THE FRONT WILL STAY FAR ENOUGH WEST THROUGH THE END OF
THE PERIOD THAT FURTHER RAIN CHANCES WILL BE QUITE LIMITED.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
HOWEVER...WITH WEAK INSTABILITY EXPECTED TO DEVELOP OVER THE
REGION BY LATE AFTERNOON...SOME POP-UP SHOWERS (AND MAYBE
THUNDERSTORMS) WILL OCCUR. A VCSH HAS BEEN INCLUDED AT ALL THE TAF
SITES TO ACCOUNT FOR THIS POSSIBILITY. THE BEST CHANCE FOR
THUNDERSTORMS WILL BE NORTH OF THE TAF SITES...THOUGH NOT TOO FAR
NORTH AND WEST OF DAYTON.
OVERNIGHT...SOME OF THE COMPUTER MODELS INDICATE THAT SCATTERED
SHOWERS MAY PERSIST. HOWEVER...THIS PROBABILITY SEEMS TOO LOW TO
INCLUDE IN THE TAFS THIS FAR OUT. THERE MAY BE ANOTHER CHANCE OF
SHOWERS AND POSSIBLY STORMS BY MID MORNING TUESDAY...WITH DAYTON
AGAIN BEING THE MORE LIKELY TAF SITE TO BE AFFECTED.
WHILE CLOUD BASES WILL BE AT VARIOUS LEVELS THROUGH THE TAF
PERIOD...THEY ARE EXPECTED TO REMAIN IN THE VFR CATEGORY. IF A
SHOWER PASSES OVER A TAF SITE...DEGRADED CONDITIONS COULD BE
EXPECTED.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE TUESDAY AND WEDNESDAY.
THUNDERSTORMS ARE LIKELY ON THURSDAY. MVFR CEILINGS ARE POSSIBLE
THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS NORMAN OK
1222 PM CDT MON APR 8 2013
.AVIATION...
18Z TAFS... MVFR CEILINGS EXPECTED AGAIN TONIGHT ACROSS THE AREA.
MODELS SUGGEST SOME DRIZZLE TO DEVELOP TUESDAY MORNING BUT WILL
HOLD OFF PUTTING IN THE TAFS FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 1044 AM CDT MON APR 8 2013/
UPDATE...
INCREASED HIGH TEMPERATURES A FEW DEGREES ACROSS SOUTHWEST
OKLAHOMA AND FAR WESTERN NORTH TEXAS THIS AFTERNOON. TWEAKED LATE
AFTERNOON/EVENING STORM CHANCES TODAY AS WELL AS SKY COVER
AND WINDS.
DISCUSSION...
THE CHALLENGE OF THE DAY IS DETERMINING WHETHER OR NOT A FEW
STORMS WILL DEVELOP ACROSS WESTERN OKLAHOMA AND WESTERN NORTH
TEXAS LATE THIS AFTERNOON AND EVENING.
BASED ON SURROUNDING RAOBS THIS MORNING...A RATHER STRONG CAP
IS IN PLACE ACROSS THE REGION. TO BREAK IT...CONVECTIVE TEMPERATURES
MUST REACH THE 84 TO 93 DEGREE RANGE...WHICH SEEMS TO ONLY BE
POSSIBLE ACROSS FAR WESTERN OKLAHOMA AND FAR WESTERN NORTH TEXAS
ACCORDING TO LATEST MODELS. SINCE THESE AREAS ARE SUNNY AT THIS
MOMENT AND BASED ON LATEST HRRR RUNS...INCREASED HIGHS IN THESE
AREAS WITH HIGHS IN THE LOWER TO PERHAPS MID 90S WEST OF A SAYRE
TO ALTUS TO SEYMOUR LINE.
FOR NOW...KEPT A 20 PERCENT CHANCE FOR STORMS MAINLY NEAR A
WOODWARD TO KNOX CITY LINE BETWEEN 4 AND 7 PM CDT...AND NEAR
AN ALVA TO WEATHERFORD TO VERNON LINE 7 PM CDT TO 1 AM CDT. IF
STORMS DEVELOP...WHICH REMAINS A BIG IF...THEY WOULD BE HIGH
BASED AT FIRST WITH DAMAGING WIND AS THE MAIN HAZARD...BUT COULD
INTENSIFY QUICKLY AS THEY MOVE EAST INTO DEEPER MOISTURE AND
BETTER INSTABILITY...SUGGESTING A LARGE HAIL AND PERHAPS A
TORNADO THREAT. CONFIDENCE OF ANY STORMS DEVELOPING THIS
AFTERNOON AND EVENING REMAINS LOW AS NOT SURE IF THE CAP CAN
BE OVERCOME...ESPECIALLY WITHOUT A MID/UPPER LEVEL TRIGGER TO
PROVIDE LIFT.
FOR THE OKLAHOMA CITY METRO AREA...THUNDERSTORMS ARE NOT
EXPECTED THROUGH MIDDAY TUESDAY.
PRODUCTS HAVE BEEN UPDATED.
MBS
FIRE WEATHER...
WILL BE CLOSE TO CRITICAL FIRE WEATHER CONDITIONS BETWEEN 2 AND 9
PM CDT TODAY ACROSS FAR WESTERN NORTH TEXAS AND FAR WESTERN
OKLAHOMA...MAINLY ALONG AND WEST OF A GAGE TO SEYMOUR LINE. DUE
TO MARGINAL WINDS AND SOME UNCERTAINTY WITH HUMIDITY LEVELS...HELD
OFF WITH A RED FLAG WARNING...BUT WILL CLOSELY MONITOR.
MBS
PREV DISCUSSION... /ISSUED 647 AM CDT MON APR 8 2013/
AVIATION...
08/12Z TAFS...PRIMARILY MVFR CIGS WITH INCREASING SOUTHERLY WIND
THROUGH THE DAY INTO TONIGHT. MVFR CONDITIONS FOR A FEW HOURS
EARLY THIS MORNING ACROSS SOUTHWEST OKLAHOMA AND KSPS BUT EXPECT
MOST OF CIGS TO SHIFT JUST EAST OF THOSE TERMINALS AFTER 15Z AND
RETURN AFTER 02Z. WEST-CENTRAL/NW OKLAHOMA TERMINALS WILL HAVE TO
DEAL WITH MVFR/IFR CONDITIONS EARLY IN FORECAST PERIOD NEAR AND
JUST NORTH OF WARM FRONT. FRONT WILL MAKE SLOW PROGRESS NORTHWARD
THIS MORNING WITH IMPROVING CONDITIONS AFTER 15-18Z. WILL NOT
INCLUDE TSRA IN ANY TERMINAL DUE TO VERY ISOLATED /IF ANY/ NATURE
LATER TODAY.
PREV DISCUSSION... /ISSUED 437 AM CDT MON APR 8 2013/
DISCUSSION...
STRONG CAP EXPECTED TO KEEP THUNDERSTORM CHANCES VERY LOW AGAIN
TODAY WITH ANY ISOLATED DEVELOPMENT NEAR DRYLINE/WARM FRONT OVER
FAR WEST/NORTHWEST OKLAHOMA. DEWPOINTS WILL BE SLIGHTLY HIGHER
TODAY AND LATEST MODELS INDICATE MORE IN THE WAY OF LOW-LEVEL
CONVERGENCE...BUT CAP WILL REMAIN QUITE STRONG. SCATTERED STORMS
THAT FIRED AROUND THE TULSA AREA FORMED ON NOSE OF LOW LEVEL JET
AND 800-700MB TIGHT BAROCLINIC ZONE. THIS ACTIVITY AND OTHER
ASSOCIATED WITH SAID TEMP GRADIENT SHOULD STAY NORTH AND EAST OF
CWA THIS MORNING.
LOW POPS WILL BE SEEN OVER A SMALL AREA OF WESTERN/NORTHERN
OKLAHOMA LATE TODAY INTO THIS EVENING WITH QUICK INCREASE IN POPS
TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING. ALTHOUGH WE CANNOT
RULE OUT A FEW STORMS IN WARM SECTOR NEAR/EAST OF DRYLINE
TUESDAY...PRIMARY FOCUS FOR WIDESPREAD THUNDERSTORMS WILL BE
STRONG COLD FRONT THAT WILL MOVE INTO NORTHWEST OKLAHOMA LATE
TUESDAY AFTERNOON AND MOVE QUICKLY SOUTHEAST OVER REGION. ALTHOUGH
SIGNIFICANT WEATHER WILL BE SEEN WITH ANY STORM THAT HAPPENS TO
DEVELOP AHEAD OF FRONT...PRIMARY IMPACTS FROM SEVERE WEATHER WILL
BE WIND/HAIL ASSOCIATED WITH SQUALL LINE. POTENTIAL FOR SEVERE
WEATHER EXPECTED TO DECREASE WITH ANY POST-FRONTAL STORMS LATE
TUESDAY NIGHT AND WEDNESDAY. MUCH COLDER AIR WILL FILTER IN BEHIND
FRONT...AND GIVEN PROGD GRADIENT AND COLD ADVECTION...WIND
ADVISORY MAY BE NEEDED TUESDAY NIGHT/EARLY WEDNESDAY MORNING.
SPEAKING OF COLD AIR...WE WILL MENTION SOME RAIN/SNOW AND SNOW
AREAS ACROSS PORTIONS OF NORTHERN AND WESTERN OKLAHOMA TUESDAY
NIGHT AND EARLY WEDNESDAY MORNING. DESPITE SOME AGGRESSIVE SNOW
OUTPUT FROM MODELS...PRECIP WILL BE ENDING AND INTRUSION OF DRY
AIR EXPECTED TO PRECLUDE ANY SIGNIFICANT ACCUMS. FREEZE LIKELY
ACROSS AT LEAST NORTHWEST THIRD OR SO OF OKLAHOMA WEDNESDAY
MORNING AND POSSIBLY OVER A MUCH LARGER AREA THURSDAY MORNING.
GIVEN THAT WE HAVE PASSED THE CLIMO FOR FREEZES OVER CENTRAL AND
SOUTHERN OKLAHOMA/NORTHERN TEXAS...FREEZE WARNINGS MAY BE
WARRANTED.
REINFORCING SHOTS OF COOLER AIR EXPECTED THROUGH FRIDAY WITH
WARMUP INCREASING OVER WEEKEND. MODELS SOMEWHAT INCONSISTENT WITH
PRECIP POTENTIAL LATE FRIDAY AND SATURDAY WITH NORTHWEST FLOW
SYSTEM...BUT WITH RUN TO RUN CONSISTENCY LESS THAN DESIRED DID NOT
INTRO POPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 77 64 75 36 / 0 10 20 70
HOBART OK 87 62 77 32 / 20 20 30 50
WICHITA FALLS TX 84 63 81 38 / 0 10 20 60
GAGE OK 84 61 71 25 / 20 10 20 30
PONCA CITY OK 75 63 74 36 / 0 10 30 70
DURANT OK 74 64 77 52 / 10 10 10 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25/25
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1114 AM PDT Mon Apr 8 2013
.SYNOPSIS...
Cool and showery weather will occur through today...with
further snow accumulations likely for the Cascade passes. The
next break in the active weather pattern will be on Tuesday but
active...showery and breezy weather will return on Wednesday. A
progressive weather regime with more showery storm systems are
expected later in the week through next weekend.
&&
.DISCUSSION...
Rest of Today...Yesterdays low pressure system remains fixed over
the Inland NW this morning per the latest visible satellite
picture...but the isallobaric analysis shows it is filling by
nearly a millibar per hour. Part of this is due to the low filling
and another portion is due to the influx of modified arctic air
spilling southwest down the Purcell Trench. The models are having
a tough time determining how far west this arctic intrusion will
spread. By 18z...NE winds are expected to overtake the northern
Palouse...Spokane Area...and eastern Columbia Basin. Once this air
arrives...dewpoints should fall and make the chances for
measurable precipitation quite small. Pops have been lowered
through the afternoon for these locations...however we won`t get
rid of them entirely. The best chances for showers this afternoon
will occur over NE and NC Washington where light showers were
persisting. Better instability is located over SE Washington and
NC Idaho per the RUC and HRRR...and this is where we would expect
to see the bulk of the convection occur this afternoon along the
remnants of the inverted surface trough axis. Model soundings over
the Blue Mountains and Lewiston area suggest convection maybe just
about deep enough to spawn an isolated thunderstorm...but its
quite borderline...so will leave it out of the forecast for now.
Much of the convection will begin to taper off overnight as
shortwave ridging begins to build in from the west. fx
&&
.AVIATION...
18Z TAFs: Weak surface low will keep unstable conditions over much
of the Inland NW again today so showers can be
expected to become more numerous...especially for PUW and LWS
where the instability is greatest. There will also be a threat of
GEG SFF and COE...however increasing E-NE flow will begin to
entrain drier air southwestward which should begin to lessen the
chances for showers and gradually raise the MVFR cigs. What time
the cigs climb above MVFR conditions is not a high confidence
forecast element...however conditional climatology suggests
sometime between 20-22z. The shower threat will decrease rapidly
overnight as ridging builds in from the west. This should bring
VFR conditions to all sites tonight through 18z Tue. Suspect there
could be some patchy fog forming overnight in the valleys of NE
and NC WA...but this should avoid all forecast sites. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 48 34 53 39 58 38 / 20 10 0 10 60 60
Coeur d`Alene 46 30 54 36 57 37 / 30 10 0 10 60 60
Pullman 47 33 54 39 59 37 / 30 20 0 10 70 70
Lewiston 53 37 58 42 65 42 / 30 10 0 10 20 50
Colville 51 31 58 37 60 36 / 40 10 10 20 60 20
Sandpoint 45 31 51 35 54 36 / 50 20 0 10 70 70
Kellogg 44 28 50 35 52 36 / 60 20 0 20 70 70
Moses Lake 54 34 61 42 65 39 / 10 0 0 0 20 10
Wenatchee 54 39 59 43 61 41 / 10 0 0 0 20 10
Omak 52 34 60 39 62 37 / 20 0 0 10 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1227 PM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
437 AM UPDATE...NOTICED THAT BOTH THE 08.00Z ECMWF AND 08.00Z/06Z
NAM INDICATE A DRY SLOT COMING THROUGH ALOFT TO SCOUR OUT THE ICE IN
THE CLOUDS FOR WEDNESDAY NIGHT AND THURSDAY. IF THIS COMES TO
FRUITION...WE MAY BE DEALING MORE WITH RAIN / FREEZING RAIN VERSUS
SNOW...AND THUS BACK TO WONDERING ABOUT OBJECT TEMPERATURES.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...THROUGH 18Z TUESDAY
1227 PM CDT MON APR 8 2013
PESKY MVFR/IFR STRATUS IN PACE ACROSS THE AREA BEHIND A DEPARTING
MID-LEVEL SHORTWAVE. VISIBLE SATELLITE WAS SHOWING SOME EROSION ON
THE SOUTHERN FRINGES OF THIS STRATUS ACROSS NORTHEAST IA INTO FAR
SOUTHWEST IA. RAP/NAM MODEL LAYER HUMIDITY AND SOUNDING
SHOWING THIS MIXING/SCATTERING REMAINING JUST SOUTH OF THE
KRST/KLSE TAF SITES THROUGH THIS AFTERNOON. SO...LOOKS LIKE KRST
WILL IMPROVE INTO MVFR CONDITIONS THIS AFTERNOON WITH KLSE REMAINING
IN MVFR CLOUDS. MESSY WEATHER PATTERN THEN SETTING UP ACROSS THE
AREA OVER THE NEXT 24 HOURS. LOW PRESSURE WILL MOVE OUT INTO THE
PLAINS TONIGHT...PUSHING A WARM FRONT AND SURGE OF MOISTURE TOWARD
THE REGION. THIS WILL LEAD TO RAIN DEVELOPING AFTER MIDNIGHT WITH
DETERIORATION IN CIGS/VIS INTO IFR RANGE AFTER 08Z.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
HYDROLOGY...AJ