Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/06/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1058 PM MDT WED APR 3 2013
.UPDATE...
ISSUED AT 905 PM MDT WED APR 3 2013
CURRENT WATER VAPOR IMAGERY INDICATING AN EMBEDDED SHORT WAVE
TRANSLATING ACROSS SOUTH CENTRAL WYOMING AND INTO NORTH CENTRAL
COLORADO AT THIS TIME. REGIONAL RADARS INDICATING SHOWERS ALONG
WITH A FEW LIGHTNING STRIKES ASSOCIATED WITH THIS SYSTEM MOVING
ACROSS NORTHERN COLORADO AT THIS TIME. LATEST NAM AND RAP HAVE
SHOWERS DIMINISHING AS THEY CONTINUE TO MOVE SOUTH AND EAST WITH
ONLY INCREASING MID AND AND HIGH LEVEL CLOUDS ACROSS SOUTH CENTRAL
AND SOUTHEAST COLORADO. HOWEVER...THE LAST FEW RUNS OF THE HRRR
IS INDICATING A FEW SHOWERS MOVING OUT ACROSS THE FRONT RANGE AND
INTO NORTHERN AND EASTERN PORTIONS OF EL PASO COUNTY AFTER
MIDNIGHT. HAVE NOT BOUGHT OFF ON THIS SCENARIO WITH SHOWERS
SEEMINGLY DIMINISHING WITH THE LOSS OF HEATING...THOUGH WILL NEED
TO MONITOR LATEST HRRR TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 313 PM MDT WED APR 3 2013
CURRENTLY...
SKIES CLEARING PRETTY QUICKLY FROM NW TO SE ACROSS THE REGION. ONLY
AREA OF CONSIDERABLE CLOUDINESS AT 2 PM WAS OVER THE FAR SE PLAINS.
Q WAS BUBBLING OVER THE S MTNS. TEMPS WERE IN THE 40S OVER THE
PLAINS WHERE THERE WAS SUN...AND 30S WHERE IT WAS CLOUDY. THE SLV
WAS IN THE 50S.
REST OF TODAY INTO TONIGHT...
RIDGING WILL BUILD OVER THE FCST AREA AND SKIES WILL CONTINUE TO
CLEAR. A FEW CONVECTIVE SHOWERS WILL BE POSSIBLE OVER THE SAN JUANS
AND S MTNS THE REST OF THIS AFTERNOON AND EARLY EVENING. OTHERWISE
EXPECT CLEARING SKIES.
THE ONLY CONCERN I HAVE FOR TONIGHT WILL BE PATCHY GROUND FOG IN
PLACES. BASED ON CURRENT RH PROGS...BEST CHANCE FOR SOME FOG WILL BE
OVER THE FAR E PLAINS...MAINLY ALONG THE ARK RVR. TEMPS TONIGHT WILL
BE COOL WITH U20S TO L30S ACROSS THE PLAINS...AND 20S VALLEYS.
THURSDAY...
500 MB RIDGE AXIS WILL BE OVER THE STATE BY LATE AFTERNOON.
TEMP-WISE...TOMORROW WILL BE QUITE A NICE DAY WITH HIGHS IN THE L70S
MOST OF THE PLAINS WITH 60S IN THE VALLEYS. SKIES WILL BE MOSTLY
SUNNY. NO PRECIP IS EXPECTED.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 313 PM MDT WED APR 3 2013
SOME ADJUSTMENTS NEEDED DURING THE LONGER TERM WITH MAIN
METEOROLOGICAL ISSUES CONTINUING TO BE TEMPERATURES...GUSTY WINDS
AT TIMES...ELEVATED FIRE WEATHER CONCERNS FROM FRIDAY AFTERNOON
INTO FRIDAY EVENING...THUNDERSTORM THREAT OVER PORTIONS OF THE FAR
EASTERN PLAINS...ESPECIALLY FROM SUNDAY EVENING INTO SUNDAY NIGHT
AND FINALLY THE IMPACT THAT UPPER SYSTEM WILL PRODUCE OVER THE
FORECAST DISTRICT EARLY NEXT WEEK.
IT STILL APPEARS THE RELATIVELY BENIGN AND MILD TO WARM
METEOROLOGICAL CONDITIONS SHOULD BE NOTED OVER THE CWFA INTO
FRIDAY...THANKS TO A TRANSITORY UPPER RIDGE MOVING ACROSS THE AREA.
IN ADDITION...ELEVATED FIRE CONCERNS ARE STILL ANTICIPATED FROM
FRIDAY AFTERNOON INTO FRIDAY EVENING...ESPECIALLY OVER PORTIONS OF
FIRE WEATHER ZONES 222/224/225/228>233 AND 235 DUE TO PROJECTED
LOW MINIMUM RELATIVE HUMIDITIES AND GUSTY WINDS AT TIMES.
AS TOUCHED UPON IN PREVIOUS DISCUSSIONS...UPPER LEVEL
DISTURBANCES...IMPACTING PRIMARILY NORTHERN PORTIONS OF THE FORECAST
DISTRICT WITH INCREASED PRECIPITATION CHANCES ARE PROJECTED TO
IMPACT THE CWFA FROM LATER FRIDAY INTO THE WEEKEND...ALLOWING FOR
SOMEWHAT COOLER TEMPERATURES AS WELL AS GUSTY WINDS AT TIMES. IN
ADDITION...INCREASED THUNDERSTORM CHANCES MAY BE NOTED OVER FAR
EASTERN PORTIONS OF THE FORECAST DISTRICT FROM SUNDAY EVENING INTO
SUNDAY NIGHT AS DEEPER ATMOSPHERIC MOISTURE INTERACTS WITH
RELATIVELY HEALTHY 0 TO 6 KM BULK SHEARS.
UPPER TROUGH SHOULD THEN IMPACT THE FORECAST DISTRICT BY EARLY NEXT
WEEK WITH THE HIGHEST POTENTIAL FOR WIDESPREAD PRECIPITATION
PROJECTED FROM LATER MONDAY INTO AT LEAST TUESDAY NIGHT. HAVE PAINTED
GENERALLY SCATTERED POPS DURING THIS TIME-FRAME WITH A POTENTIAL
FOR HEALTHY ACCUMULATING SNOW...ESPECIALLY OVER HIGHER TERRAIN
AREAS. WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY.
GUSTY WINDS WILL BE POSSIBLE FROM FRIDAY INTO FRIDAY NIGHT AND THEN
AGAIN FROM NEXT TUESDAY INTO TUESDAY NIGHT. WARMEST TEMPERATURES OF
THE LONGER TERM ARE EXPECTED FRIDAY WHILE COOLEST CONDITIONS ARE
ANTICIPATED BY NEXT TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1058 PM MDT WED APR 3 2013
VFR CONDITIONS EXPECTED AT ALL TAF SITES THROUGH THE NEXT 24
HOURS. A MINOR DISTURBANCE MOVING ACROSS NORTHEASTERN COLORADO
WILL SPREAD SOME MID AND HIGH LEVEL MOISTURE ACROSS THE AREA
THROUGH THE EARLY MORNING HOURS. THIS SYSTEM WILL ALSO SEND A
WEAK BACK DOOR FRONT ACROSS THE EASTERN PLAINS THROUGH THE
OVERNIGHT HOURS. LIGHT NORTHERLY WINDS BEHIND WEAK FRONT LOOKS
TO INHIBIT FOG FORMATION ACROSS THE EASTERN PLAINS...WITH A
DIURNAL WIND REGIME EXPECTED ONCE AGAIN THURSDAY AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...HODANISH
LONG TERM...77
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1000 AM EDT Thu Apr 4 2013
.NEAR TERM [Rest of Today]...
Updated at: 1000 AM EDT
Early indications this morning are that severe weather potential is
becoming increasingly marginal for today across our area. Limiting
factors include:
1. Cirrus shield currently spread north from convection over the
C/EC Gulf of Mexico that may limit heating, or delay the
scattering of low cloud decks
2. A pronounced inversion around 650mb (via 12z TAE sounding) due
to the arrival of an EML aloft.
3. Deeper moisture situated well to the south over the Gulf and
the Florida peninsula.
Essentially, the atmosphere is going to have to do a lot of work in
order to be more conducive for severe thunderstorms, and that is
looking less and less likely with time in our forecast area. 12z RAP
analysis shows that at 700mb, the pocket of warmest air is actually
situated just overhead at the moment. Meanwhile, a subtle shortwave
and jet max aloft near the Louisiana coastline (per water vapor) was
propagating ENE, and RAP analysis suggested that 700mb temperatures
were about 2-3C cooler near this feature. Therefore, it`s possible
that as mid-level height falls commence and stronger upper level
forcing arrives, that the inversion layer aloft will slowly erode.
However, even 2-3C of cooling in that layer would still leave us
with a rather marginal instability profile. What would be most
likely would be shallow rain showers with isolated thunderstorms,
increasing in coverage for a brief time as the shortwave approaches.
Extrapolation of the shortwave would take it into our area around
18-21z. The changes that were made to the grids to account for all
this was to reduce the sensible weather across most of the area to
just rain showers with isolated thunderstorms, and time the peak in
PoPs more for the early to mid afternoon.
Despite all of these factors, it is not possible to totally rule out
a stronger storm or two this afternoon. There is still a fair amount
of uncertainty in the assessment of various mesoscale features, so
we will continue to highlight a risk of severe storms in the HWO.
Any strong or severe storms, however, should be rather isolated.
&&
.SHORT TERM [Tonight Through Saturday]...
By this evening, the severe potential, and possibly even the thunder
potential will have diminished greatly from this afternoon. The only
exception may be a few strong storms remaining across the extreme
southeast Big Bend of Florida. Elsewhere light rain will persist
through the night, especially across Georgia where the upper level
shortwave will be able to tap into the best remaining moisture. A
dry slot will likely spread from southwest to northeast through the
night, putting a stop to the rain across portions of the Florida
Panhandle and southeast Alabama. Showers will come to an end quickly
on Friday, but clouds should remain for much of the day. This will
hold temperatures in the 60s region-wide, with lower 60s possible
across portions of central Georgia. Overnight Friday, temperatures
will fall to a few degrees below seasonal averages, in the middle
40s for most locations. Dry conditions, mostly clear skies, and
seasonal temperatures will finish off the period on Saturday.
&&
.LONG TERM [Saturday Night through Wednesday]...
The bulk of the extended forecast looks to be dry with gradually
warming temperatures as a ridge of surface high pressure shifts from
over the area on Saturday, to well off the Atlantic coast by
Tuesday. This evolution will set up return flow early in the next
work week, and highs into the 80s look likely.
&&
.AVIATION [through 12 UTC Friday]...
Occasional light rain is likely this morning. However, scattered
+SHRA/TSRA will develop later this morning, affecting KECP, KTLH,
and KVLD with locally gusty winds and heavy downpours until mid
afternoon. LIFR-IFR cigs will gradually lift to low-end MVFR levels
by late morning or early afternoon. Although most of the rain will
move east of the region later this afternoon, IFR-LIFR cigs are
likely to return to all terminals tonight.
&&
.MARINE...
Advisory level conditions are expected ahead of developing low
pressure today. In the wake of the low, another brief round of
advisory conditions are anticipated. Winds and seas will fall below
headline levels by the weekend, and remain that way through at least
early next week under the influence of high pressure.
&&
.FIRE WEATHER...
Moist conditions will persist through Friday, helping to keep ERC
values low. A drier airmass will move into the region Saturday, but
at this time it doesn`t appear that Red Flag conditions are likely,
especially since the winds won`t be very strong and the fuels may be
rather damp.
&&
.HYDROLOGY...
With round 1 of the rain complete, we have seen storm totals thus
far between an inch and an inch and a half across the southeast Big
Bend of Florida and around a half of an inch across portions of
south central Georgia east of the Flint River and along the Florida
Panhandle coast.
The light rain from overnight will continue to gradually spread
north through the first part of the day today. Later today,
another round of moderate to heavy rain is expected, with the bulk
of the rain falling along and east of the Flint and Apalachicola
Rivers. In these locations another 1 to 2 inches will be possible,
with the highest amounts expected across the southeast Big Bend,
in the lower Suwannee River basins. With the eastward shift in
expected rainfall, ensemble guidance suggests that most area
rivers will only flirt with the lower end of Action stage. In
fact, the lower Suwannee appears capable of handling the projected
rainfall without climbing to Action stage for most of our forecast
points. When all is said and done there should be little in the
way of impacts along area rivers this weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 73 56 67 46 76 / 50 40 20 0 0
Panama City 71 57 67 53 74 / 40 40 20 0 0
Dothan 66 51 66 44 74 / 30 40 20 0 0
Albany 64 48 65 45 75 / 40 40 30 0 0
Valdosta 71 55 66 46 76 / 50 40 40 10 0
Cross City 73 62 70 45 78 / 40 50 30 10 0
Apalachicola 70 59 66 52 71 / 40 30 20 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...Small Craft Advisory until 5 PM EDT Friday for Gulf of Mexico
waters from Destin to the Suwannee River out to 60 NM.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Harrigan
LONG TERM...Lamers
AVIATION...Fournier
MARINE...Harrigan
FIRE WEATHER...Fournier
HYDROLOGY...Harrigan
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
630 AM EDT Thu Apr 4 2013
...There is a slight risk for severe weather today...
.NEAR TERM [Today]...
The 03 UTC regional surface analysis showed a quasi-stationary front
from north FL, to just south of the LA coast, to the southwest Gulf
of Mexico. While a frontal wave appeared to be developing (as
predicted by the NWP guidance) south of LA, the only low that I was
able to close off appeared to be more of a mesoscale low about
30 miles south of Apalachicola, perhaps leftover from the wake low
that brought some gusty winds to portions of our forecast area
Wednesday afternoon and evening. Vapor imagery and upper air data
showed an approaching trough centered over OK, but there were a few
minor short waves well out ahead of this main system.
All of the statistical and dynamical NWP guidance points to a rainy
day for our region today, though just how much rain, and how stormy,
is rather complicated. Since most of the 00 UTC NWP guidance didn`t
initialize the meso low south of Apalachicola, it`s unclear how well
they will handle the frontal system and main frontal wave developing
to the west. Much of our thinking is based on the recent RAP run,
which did initialize the various features quite well. We expect
quite a bit of light rain early this morning, followed by increasing
heavier showers and thunderstorms later this morning and afternoon
as the low moves inland over the FL Panhandle. The band(s) of
convection will move into our eastern zones this afternoon. Much of
our forecast area is likely to get an additional 1 to
2 inches of rain from this system.
The latest NSSL WRF, NCEP ARW/NMM, and our local 4km WRF show a
couple of impressive tracks of max hourly updraft helicity (in terms
of magnitude and longevity) this afternoon. The same can be said for
integrated graupel. This would imply a threat for isolated supercell
thunderstorms, capable of producing severe hail, damaging wind
gusts, and/or even an isolated tornado. While this threat appears
highest over the Gulf coastal waters and the FL Peninsula, there is
a portion of our forecast area that is at risk as well- mainly along
and south of a line from Apalachicola, through Tallahassee, to Moody
AFB, Valdosta. This threat would be from late morning through mid to
late afternoon. Actually, much of our forecast area is in a "Slight
Risk" (15% probability of severe hail/wind, 5% tornado) of severe
storms, but it may be more difficult to generate severe storms
farther west and north than the section we just discussed, as the
best deep layer moisture, forcing, and the 850mb jet stream will
likely be farther east.
&&
.SHORT TERM [Tonight Through Saturday]...
By this evening, the severe potential, and possibly even the
thunder potential will have diminished greatly from this
afternoon. The only exception may be a few strong storms remaining
across the extreme southeast Big Bend of Florida. Elsewhere light
rain will persist through the night, especially across Georgia
where the upper level shortwave will be able to tap into the best
remaining moisture. A dry slot will likely spread from southwest
to northeast through the night, putting a stop to the rain across
portions of the Florida Panhandle and southeast Alabama. Showers
will come to an end quickly on Friday, but clouds should remain
for much of the day. This will hold temperatures in the 60s
region-wide, with lower 60s possible across portions of central
Georgia. Overnight Friday, temperatures will fall to a few degrees
below seasonal averages, in the middle 40s for most locations. Dry
conditions, mostly clear skies, and seasonal temperatures will
finish off the period on Saturday.
&&
.LONG TERM [Saturday Night through Wednesday]...
The bulk of the extended forecast looks to be dry with gradually
warming temperatures as a ridge of surface high pressure shifts
from over the area on Saturday, to well off the Atlantic coast by
Tuesday. This evolution will set up return flow early in the next
work week, and highs into the 80s look likely.
&&
.AVIATION [through 12 UTC Friday]...
Occasional light rain is likely this morning. However, scattered
+SHRA/TSRA will develop later this morning, affecting KECP, KTLH,
and KVLD with locally gusty winds and heavy downpours until mid
afternoon. LIFR-IFR cigs will gradually lift to low-end MVFR levels
by late morning or early afternoon. Although most of the rain will
move east of the region later this afternoon, IFR-LIFR cigs are
likely to return to all terminals tonight.
&&
.MARINE...
Advisory level conditions are expected ahead of developing low
pressure today. In the wake of the low, another brief round of
advisory conditions are anticipated. Winds and seas will fall
below headline levels by the weekend, and remain that way through
at least early next week under the influence of high pressure.
&&
.FIRE WEATHER...
Moist conditions will persist through Friday, helping to keep ERC
values low. A drier airmass will move into the region Saturday, but
at this time it doesn`t appear that Red Flag conditions are likely,
especially since the winds won`t be very strong and the fuels may be
rather damp.
&&
.HYDROLOGY...
With round 1 of the rain complete, we have seen storm totals thus
far between an inch and an inch and a half across the southeast
Big Bend of Florida and around a half of an inch across portions
of south central Georgia east of the Flint River and along the
Florida Panhandle coast.
The light rain from overnight will continue to gradually spread
north through the first part of the day today. Later today,
another round of moderate to heavy rain is expected, with the bulk
of the rain falling along and east of the Flint and Apalachicola
Rivers. In these locations another 1 to 2 inches will be possible,
with the highest amounts expected across the southeast Big Bend,
in the lower Suwannee River basins. With the eastward shift in
expected rainfall, ensemble guidance suggests that most area
rivers will only flirt with the lower end of Action stage. In
fact, the lower Suwannee appears capable of handling the projected
rainfall without climbing to Action stage for most of our forecast
points. When all is said and done there should be little in the
way of impacts along area rivers this weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 73 56 67 46 76 / 80 60 20 0 0
Panama City 71 57 67 53 74 / 70 40 20 0 0
Dothan 66 51 66 44 74 / 70 50 20 0 0
Albany 64 48 65 45 75 / 80 70 30 0 0
Valdosta 71 55 66 46 76 / 90 70 40 10 0
Cross City 73 62 70 45 78 / 90 80 30 10 0
Apalachicola 70 59 66 52 71 / 70 40 20 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...Small Craft Advisory until 5 PM EDT Friday for Gulf of Mexico
waters from Destin to the Suwannee River out to 60 NM.
&&
$$
NEAR TERM...Fournier
SHORT TERM...Harrigan
LONG TERM...Lamers
AVIATION...Fournier
MARINE...Harrigan
FIRE WEATHER...Fournier
HYDROLOGY...Harrigan
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
347 AM EDT Thu Apr 4 2013
...There is a slight risk for severe weather today...
.NEAR TERM [Today]...
The 03 UTC regional surface analysis showed a quasi-stationary front
from north FL, to just south of the LA coast, to the southwest Gulf
of Mexico. While a frontal wave appeared to be developing (as
predicted by the NWP guidance) south of LA, the only low that I was
able to close off appeared to be more of a mesoscale low about
30 miles south of Apalachicola, perhaps leftover from the wake low
that brought some gusty winds to portions of our forecast area
Wednesday afternoon and evening. Vapor imagery and upper air data
showed an approaching trough centered over OK, but there were a few
minor short waves well out ahead of this main system.
All of the statistical and dynamical NWP guidance points to a rainy
day for our region today, though just how much rain, and how stormy,
is rather complicated. Since most of the 00 UTC NWP guidance didn`t
initialize the meso low south of Apalachicola, it`s unclear how well
they will handle the frontal system and main frontal wave developing
to the west. Much of our thinking is based on the recent RAP run,
which did initialize the various features quite well. We expect
quite a bit of light rain early this morning, followed by increasing
heavier showers and thunderstorms later this morning and afternoon
as the low moves inland over the FL Panhandle. The band(s) of
convection will move into our eastern zones this afternoon. Much of
our forecast area is likely to get an additional 1 to
2 inches of rain from this system.
The latest NSSL WRF, NCEP ARW/NMM, and our local 4km WRF show a
couple of impressive tracks of max hourly updraft helicity (in terms
of magnitude and longevity) this afternoon. The same can be said for
integrated graupel. This would imply a threat for isolated supercell
thunderstorms, capable of producing severe hail, damaging wind
gusts, and/or even an isolated tornado. While this threat appears
highest over the Gulf coastal waters and the FL Peninsula, there is
a portion of our forecast area that is at risk as well- mainly along
and south of a line from Apalachicola, through Tallahassee, to Moody
AFB, Valdosta. This threat would be from late morning through mid to
late afternoon. Actually, much of our forecast area is in a "Slight
Risk" (15% probability of severe hail/wind, 5% tornado) of severe
storms, but it may be more difficult to generate severe storms
farther west and north than the section we just discussed, as the
best deep layer moisture, forcing, and the 850mb jet stream will
likely be farther east.
&&
.SHORT TERM [Tonight Through Saturday]...
By this evening, the severe potential, and possibly even the
thunder potential will have diminished greatly from this
afternoon. The only exception may be a few strong storms remaining
across the extreme southeast Big Bend of Florida. Elsewhere light
rain will persist through the night, especially across Georgia
where the upper level shortwave will be able to tap into the best
remaining moisture. A dry slot will likely spread from southwest
to northeast through the night, putting a stop to the rain across
portions of the Florida Panhandle and southeast Alabama. Showers
will come to an end quickly on Friday, but clouds should remain
for much of the day. This will hold temperatures in the 60s
region-wide, with lower 60s possible across portions of central
Georgia. Overnight Friday, temperatures will fall to a few degrees
below seasonal averages, in the middle 40s for most locations. Dry
conditions, mostly clear skies, and seasonal temperatures will
finish off the period on Saturday.
&&
.LONG TERM [Saturday Night through Wednesday]...
The bulk of the extended forecast looks to be dry with gradually
warming temperatures as a ridge of surface high pressure shifts
from over the area on Saturday, to well off the Atlantic coast by
Tuesday. This evolution will set up return flow early in the next
work week, and highs into the 80s look likely.
&&
.AVIATION [Beginning 07Z Thursday]...
Occasional light rain (IFR-MVFR vis) is likely through today and
into tonight. However, scattered +SHRA/TSRA will develop later this
morning, affecting the terminals with locally gusty winds and heavy
downpours until mid to late afternoon. IFR to occasionally LIFR cigs
are likely through this morning. They will gradually lift to low-end
MVFR levels by late morning or early afternoon. The guidance differs
on how long these cigs will persist after 00 UTC tonight, so we will
just keep the MVFR cigs through the end of this TAF package.
&&
.MARINE...
Advisory level conditions are expected ahead of developing low
pressure today. In the wake of the low, another brief round of
advisory conditions are anticipated. Winds and seas will fall
below headline levels by the weekend, and remain that way through
at least early next week under the influence of high pressure.
&&
.FIRE WEATHER...
Moist conditions will persist through Friday, helping to keep ERC
values low. A drier airmass will move into the region Saturday, but
at this time it doesn`t appear that Red Flag conditions are likely,
especially since the winds won`t be very strong and the fuels may be
rather damp.
&&
.HYDROLOGY...
With round 1 of the rain complete, we have seen storm totals thus
far between an inch and an inch and a half across the southeast
Big Bend of Florida and around a half of an inch across portions
of south central Georgia east of the Flint River and along the
Florida Panhandle coast.
The light rain from overnight will continue to gradually spread
north through the first part of the day today. Later today,
another round of moderate to heavy rain is expected, with the bulk
of the rain falling along and east of the Flint and Apalachicola
Rivers. In these locations another 1 to 2 inches will be possible,
with the highest amounts expected across the southeast Big Bend,
in the lower Suwannee River basins. With the eastward shift in
expected rainfall, ensemble guidance suggests that most area
rivers will only flirt with the lower end of Action stage. In
fact, the lower Suwannee appears capable of handling the projected
rainfall without climbing to Action stage for most of our forecast
points. When all is said and done there should be little in the
way of impacts along area rivers this weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 73 56 67 46 76 / 80 60 20 0 0
Panama City 71 57 67 53 74 / 70 40 20 0 0
Dothan 66 51 66 44 74 / 70 50 20 0 0
Albany 64 48 65 45 75 / 80 70 30 0 0
Valdosta 71 55 66 46 76 / 90 70 40 10 0
Cross City 73 62 70 45 78 / 90 80 30 10 0
Apalachicola 70 59 66 52 71 / 70 40 20 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...Small Craft Advisory until 5 PM EDT Friday for Gulf of Mexico
waters from Destin to the Suwannee River out to 60 NM.
&&
$$
NEAR TERM...Fournier
SHORT TERM...Harrigan
LONG TERM...Lamers
AVIATION...Fournier
MARINE...Harrigan
FIRE WEATHER...Fournier
HYDROLOGY...Harrigan
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
956 PM CDT FRI APR 5 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 640 PM CDT FRI APR 5 2013
VFR CONDITIONS PREDOMINANT THROUGH MUCH OF TAF CYCLE. LOW PRESSURE
OVER SOUTHERN NEBRASKA WILL SLIDE EAST AND LIFT WARM FRONT THROUGH
THE TERMINALS LATE TONIGHT AND SATURDAY MORNING WHICH WILL BE
ACCOMPANIED BY SCATTERED SHOWERS. A COLD FRONT WILL FOLLOW FOR
SATURDAY AFTERNOON AND EVENING WITH A BETTER COVERAGE OF
SHOWERS...WITH A FEW THUNDERSTORMS POSSIBLE. POTENTIAL STILL
EXISTS FOR LOW LEVEL WIND SHEAR LATE THIS EVENING INTO THE EARLY
MORNING... HOWEVER SURFACE WINDS WILL BE INCREASING AT SAME TIME
ABOVE 10 KTS AND GUSTY... THUS LEFT OUT MENTION. BREEZY TO WINDY
CONDITIONS WILL PREVAIL MUCH OF SATURDAY WITH WINDS VEERING FROM
SE TO W/SW AT 15 TO 25 KTS WITH SOME GUSTS OF 30-35 KTS POSSIBLE
AT TIMES. POTENTIAL FOR MVFR CONDITIONS TO DEVELOP MAINLY SATURDAY
AFTERNOON INTO EVENING WITH THE COLD FRONT.
&&
.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 QUAD CITIES IA IL
701 PM CDT FRI APR 5 2013
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 640 PM CDT FRI APR 5 2013
VFR CONDITIONS PREDOMINANT THROUGH MUCH OF TAF CYCLE. LOW PRESSURE
OVER SOUTHERN NEBRASKA WILL SLIDE EAST AND LIFT WARM FRONT THROUGH
THE TERMINALS LATE TONIGHT AND SATURDAY MORNING WHICH WILL BE
ACCOMPANIED BY SCATTERED SHOWERS. A COLD FRONT WILL FOLLOW FOR
SATURDAY AFTERNOON AND EVENING WITH A BETTER COVERAGE OF
SHOWERS...WITH A FEW THUNDERSTORMS POSSIBLE. POTENTIAL STILL
EXISTS FOR LOW LEVEL WIND SHEAR LATE THIS EVENING INTO THE EARLY
MORNING... HOWEVER SURFACE WINDS WILL BE INCREASING AT SAME TIME
ABOVE 10 KTS AND GUSTY... THUS LEFT OUT MENTION. BREEZY TO WINDY
CONDITIONS WILL PREVAIL MUCH OF SATURDAY WITH WINDS VEERING FROM
SE TO W/SW AT 15 TO 25 KTS WITH SOME GUSTS OF 30-35 KTS POSSIBLE
AT TIMES. POTENTIAL FOR MVFR CONDITIONS TO DEVELOP MAINLY SATURDAY
AFTERNOON INTO EVENING WITH THE COLD FRONT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...DLF
AVIATION...05
AREA FORECAST DISCUSSION
NWS TOPEKA KS
334 PM CDT THU APR 4 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 306 PM CDT THU APR 4 2013
LIGHT SURFACE PRESSURE GRADIENT IS EVIDENT IN 20Z RAP ANALYSIS. THIS
LIGHT PRESSURE GRADIENT IS RESPONSIBLE FOR LIGHT WINDS WHICH ARE
EVIDENT IN SURFACE OBSERVATIONS ACROSS THE FORECAST AREA THIS
AFTERNOON. EXPECT THESE LIGHT WINDS TO EVENTUALLY SHIFT TO THE SOUTH
OVERNIGHT TONIGHT AS A SURFACE LOW COMES INTO FORMATION OVER THE
HIGH PLAINS. SOUTHERLY WINDS WILL INCREASE THROUGH THE DAY ON FRIDAY
TO AROUND 20 TO 25 MPH...WITH GUSTS TO AROUND 30 MPH. DEEP MIXING
WILL CAUSE ALLOW FOR LOW LEVEL WINDS AROUND 850 MB TO COME TO THE
SURFACE...WHICH MAY BRING WARMER/DRYER CONDITIONS AND STRONGER WIND
GUSTS. THIS WILL HAVE FIRE WEATHER IMPLICATIONS...WHICH ARE
DISCUSSED IN THE FIRE WEATHER DISCUSSION BELOW. AT THIS TIME EXPECT
VERY HIGH FIRE DANGER FOR MOST OF THE AREA THROUGH THE DAY ON
FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 306 PM CDT THU APR 4 2013
FRIDAY NIGHT THROUGH SUNDAY...FRIDAY NIGHT LEE SIDE LOW PRESSURE
DEEPENS OVER THE HIGH PLAINS INCREASING THE PRESSURE GRADIENT
ACROSS THE AREA. THEREFORE THE WINDS WILL CONTINUE TO BE GUSTY
THROUGH THE OVERNIGHT HOURS ESPECIALLY ACROSS EASTERN KANSAS. THIS
WILL KEEP LOW TEMPERATURES FRIDAY NIGHT IN THE LOW 50S. A
SOUTHWESTERLY LOW LEVEL JET INCREASES FRIDAY NIGHT BRINGING
LIMITED MOISTURE TO THE REGION. MEANWHILE A SHORTWAVE ADVANCES
EASTWARD INTO NEBRASKA AND EVENTUALLY IOWA ON SATURDAY. IT APPEARS
THAT THE STRONGER LIFT ASSOCIATED WITH THE WAVE WILL BE NORTH OF
THE AREA FRIDAY NIGHT AND SATURDAY MORNING. THERE IS SLIGHT CHANCE
OF SOME WEAK LIFT EXTENDING SOUTH INTO KANSAS SO COULD NOT RULE
OUT AN ISOLATED SHOWER FRIDAY NIGHT. A WEAK COLD FRONT ASSOCIATED
WITH THE WAVE WILL PUSH SOUTHWARD THROUGH THE AREA DURING THE DAY
ON SATURDAY SHIFTING THE WINDS TO THE NORTH. THE FRONT WILL
RETREAT BACK TO THE NORTH ON SUNDAY AND SETS UP SOMEWHERE IN
NORTHEAST KANSAS. A WEAK SHORTWAVE EMBEDDED IN THE ZONAL MID LEVEL
FLOW PROGRESSES EASTWARD ACROSS KANSAS DURING THE DAY PROVIDING
LAGER SCALE LIFT. SOUTHERLY LOW LEVEL FLOW WILL INCREASE THE
MOISTURE RETURN ACROSS THE AREA AS ML CAPE VALUES APPROACH 500
J/KG AIDING IN THUNDERSTORM DEVELOPMENT. MID LEVEL FLOW ALSO
INCREASES SUNDAY WITH 0-6 KM BULK SHEAR VALUES AROUND 40 KTS WHICH
SUPPORTS THE CHANCE OF STRONGER ORGANIZED THUNDERSTORMS SUNDAY
AFTERNOON AND OVERNIGHT.
EXTENDED FORECAST (SUN NIGHT-THURS)...AN ACTIVE PATTERN SETTING UP
THROUGH THIS PERIOD...AND SEVERE WEATHER APPEARS INCREASINGLY
LIKELY....HOWEVER TIMING AND PLACEMENT REMAINS SOMEWHAT
UNCERTAIN. SUNDAY NIGHT THE GFS AND A SOMEWHAT FASTER EC BRING A
SHORTWAVE OVER THE WARMFRONT PROGGED E/W OVER OUR AREA...WITH THE
EC HOLDING THE FRONT FARTHER SOUTH THAN THE GFS. ENOUGH CAPE AND
SHEAR PRESENT THAT SOME OF THE STORMS OVERNIGHT COULD BRING HAIL.
THE ENSUING WEATHER FOR MONDAY WILL BE DEPENDENT ON HOW FAR NORTH
THE WARMFRONT LIFTS DURING THE DAY. EC AND GFS BOTH BREAK OUT
CONVECTION NEAR THE BOUNDARY AND LESS SO IN THE WARM SECTOR MONDAY
EVENING THROUGH THE MORNING HOURS ON TUESDAY. SEVERE WEATHER
POTENTIAL CONTINUES TO INCREASE INTO TUESDAY AND TUESDAY
AFTERNOON AS WESTERN TROF APPROACHES...AND SHEAR AND INSTABILITY
ALSO INCREASE AND MOVE NORTH ACROSS THE CWA WITH THE WARM SECTOR.
DIFFERENCES INCREASE BEYOND TUESDAY AS GFS MOVES THE COLDFRONT
THROUGH QUICKLY WITH EC DROPPING A CLOSED UPPER LOW ACROSS EASTERN
KANSAS AND THE FRONT MOVING THROUGH WEDNESDAY EVENING. WHILE
WED/THURS WILL BRING A COOL END OF THE WEEK...MUCH UNCERTAINTY
WITH PRECIP AMOUNTS AND TYPES. 67
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1217 PM CDT THU APR 4 2013
EXPECT VFR CONDITIONS THROUGH FORECAST PERIOD WITH INCREASING
SOUTHERLY WINDS FRIDAY MORNING/AFTERNOON 15 TO 25 MPH GUSTING TO
30 MPH.
JL
&&
.FIRE WEATHER...
ISSUED AT 242 PM CDT THU APR 4 2013
WINDS ON FRIDAY WILL CHANGE FROM WNW OVERNIGHT TO THE SOUTH BY
EARLY FRIDAY MORNING. BY FRIDAY AFTERNOON A STRONG SURFACE
PRESSURE GRADIENT WILL FORM A CROSS CENTRAL AND EASTERN KANSAS
CAUSING THE SOUTHERLY WINDS TO INCREASE TO AROUND 20 TO 25 MPH.
DEEP MIXING TO AROUND 3000 FEET WILL ALLOW FOR SOME 30 TO 35 MPH
WINDS TO REACH THE SURFACE AS WIND GUSTS LATER IN THE AFTERNOON
ON FRIDAY. AT THIS TIME IT LOOKS AS THOUGH DEWPOINTS IN THE LOWER
40S WILL PUSH NORTHWARD INTO THE AREA. THIS WILL KEEP RH VALUES IN
THE 30 TO 40 PERCENT RANGE...HOWEVER SHOULD DEEPER MIXING OCCUR
THE DEWPOINTS COULD GO A BIT LOWER THAN CURRENTLY FORECAST...WHICH
WOULD CAUSE RH VALUES TO DIP CLOSER TO 30 PERCENT. SINCE THE RH
VALUES SHOULD REMAIN ABOVE 30 PERCENT WILL NOT ISSUE ANY KIND OF
FIRE WEATHER HEADLINE...BUT STAY TUNED TO FORECAST UPDATES THROUGH
THE DAY ON FRIDAY FOR MORE INFORMATION.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
MID RANGE...SANDERS
LONG TERM...67
AVIATION...LEIGHTON
FIRE WEATHER...LEIGHTON
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1127 AM CDT THU APR 4 2013
.UPDATE...
UPDATED AVIATION SECTION FOR 18Z TAFS
ISSUED AT 928 AM CDT THU APR 4 2013
UPDATED THE GRIDS TO BETTER REFLECT ONGOING TRENDS. FARTHER SOUTH
SHIFT IN THE MODELS LAST 24 HOURS WORKING OUT OK. ESSENTIALLY WILL
BE A SHARP CUT OFF LINE FROM LIGHT RAINS AND SPRINKLES TO DRY
CONDITIONS. TRIED TO BETTER REFLECT THIS IN THE POP GRIDS. NOT SURE
HOW FAR NORTH THE LIGHT RAINS WILL BE ABLE TO MAKE IT. RAP MODELS
SUGGESTS NOT MUCH FARTHER. GIVEN THE VERY DRY AIR SEEN ON 12 UPA
DATA AT H9 AND H8...THAT APPEARS REASONABLE...ALTHOUGH WILL HEDGE
JUST A TAD FARTHER NORTH THAN THE RAP. BROUGHT TEMPS DOWN A BIT
CLOSE TO THE TN/AR BORDERS...ESPECIALLY OVER WEST KY NEAR THE TN
STATE LINE. NORTH TOWARD I-64 WHERE SUN IS PRESENT TO START THE
DAY...AND DRY AIR HOLDS...TEMPS SHOULD HAVE NO TROUBLE RISING
STEADILY TO HIGHS IN THE MID TO UPPER 50S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 154 AM CDT THU APR 4 2013
RADAR SHOWS RETURNS TO OUR SOUTH PRODUCING SOME LIGHT RAIN. MODELS
LIFT THIS LIGHT RAIN NORTHWARD TODAY...PEAKING THIS AFTERNOON...THEN
SUBSIDING AND EVENTUALLY ENDING TONIGHT. THIS OCCURS AS AN UPPER
LEVEL LOW MOVES FROM THE SRN PLAINS ACROSS THE MID-LOWER MS RIVER
VALLEY. THE 00Z MODELING TRACK OF THIS DRIVING FEATURE IS SLIGHTLY
FURTHER SOUTH THAN PREVIOUS RUNS...SO POPS WILL BE SLIGHTLY LESS
THAN LAST NIGHT/PREVIOUS PACKAGES. OTHERWISE LITTLE CHANGE TO NEAR
TERM FORECAST.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 154 AM CDT THU APR 4 2013
THE DRYING/WARMING WEEKEND IS STILL ON TAP. THE FLOW BECOMES
LARGELY ZONAL AND ACTIVE...WITH A FRONT LAYING ACROSS/JUST TO OUR
NORTH BY SUNDAY AND WAVES OF ENERGY RIDING ALONG IT. DEPENDING
UPON WHERE THIS SETS UP EXACTLY...WE SHOULD SEE POPS ENTER THE
FORECAST BY SUNDAY/MARKING THE BEGINNING OF AN ACTIVE/PERHAPS
INCREASINGLY WET PATTERN AS WE MOVE INTO THE MID WEEK NEXT. THE
EXTENDED RANGE MODELS DEVELOP LARGE SCALE TROFFING OVER THE
CENTRAL U.S....AND THIS REALLY OPENS THE SWLYS ALOFT OVER US (WITH
HIGH PRESSURE OFF THE SE U.S.) AND MAKES FOR A WET/ACTIVE MID
WEEK. THIS INCLUDES AN INCREASING/DAILY POP/THUNDER WHICH MAY
REACH INTO THE LIKELY CATEGORY BUT FOR NOW WE REMAIN AT HIGH
CHANCE AND WILL ADJUST WITH TIME FROM DAY 7.
&&
.AVIATION...
ISSUED AT 1127 AM CDT THU APR 4 2013
WIDESPREAD MID AND HIGH CLOUDS ASSOCIATED WITH A STRONG UPPER LEVEL
LOW PASSING TO OUR SOUTH WILL PERSIST THROUGH EARLY THIS EVENING.
LOW CLOUDS WERE LURKING JUST TO THE SOUTHEAST OF KPAH AT 17Z.
THESE LOWER CLOUDS MAY MOVE INTO THE KPAH AREA THIS AFTERNOON...BUT
THE PROBABILITY WAS TOO LOW TO MENTION CIGS. OPTED INSTEAD TO
MENTION A SCATTERED CLOUD DECK AROUND 4K FEET. SKIES WILL BECOME
CLEAR BY 03Z WITH LIGHT WINDS TONIGHT. WINDS WILL BECOME NORTH
AROUND 5 TO 10 KT FRIDAY MORNING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
636 PM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST FROM THE GULF COAST THROUGH TONIGHT.
THIS AREA OF LOW PRESSURE TRACKS ALONG THE SOUTHEAST COAST
OVERNIGHT BEFORE SLIDING OFF THE MID ATLANTIC COAST FRIDAY. HIGH
PRESSURE BUILDS OVER THE REGION SATURDAY AND SHIFTS OFFSHORE
SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
UPDATED GRIDS/ZFP PER RAPIDLY CHANGING CNDTNS ACROSS THE FA ATTM.
NMRS RPTS OF SLEET MIXING IN WITH THE RAIN AT THE ONSET AS FAR
EAST AS VA BCH...SO ADDED IP TO THE GRIDS NEXT FEW HRS. ALSO...DUE
TO THE LARGE TMP/DP TMPS GAP...SFC TMPS QUICKLY FALLING INTO THE
U30S-L40S WHERE PCPN CONTS TO SATURATE THE LYR. THUS...MADE CHANGES
TO TMP GRIDS. CHALLENGING TMP FCST NEXT 6-12 HRS AS READINGS XPCTD
TO LEVEL OFF AT SOME POINT ONCE THE RAIN SATURATES COLUMN THEN STDY
OR SLOWLY RISE AFTR MIDNIGHT IN ADVANCE OF SFC LOW. TMPS MAY EVEN
RISE INTO THE 50S ACROSS NRN OB/VA BCH AREAS LATE TONITE B4 FALLING
BACK INTO THE 40S ONCE THE LOW MOVES NE.
PVS DSCN:
LATEST UPPER AIR ANALYSIS SHOWS A NORTHERN STREAM TROUGH TREKKING
ACROSS ONTARIO THIS AFTN, AS A SOUTHERN STREAM TROUGH IS NOW
ORIENTED OVER TEXARKANA/SOUTHERN MS VLY. AT THE SURFACE, WEAKENING
~1028MB SFC HIGH PRESSURE NOW ORIENTED JUST OFFSHORE, SETTING UP A
HYBRID COLD AIR DAMMING WEDGE STRUCTURE OVER THE REGION. TO THE
SOUTHWEST, A 1012MB LOW PRESSURE CENTER WAS CENTERED OVER THE FL
PANHANDLE...WITH INVERTED COASTAL TROUGH ANALYZED OFFSHORE OF THE
GA/SC COAST.
LOW PRESSURE OVER THE SOUTHEAST WILL LIFT NORTHEAST AS MS VLY
TROUGH WOBBLES EAST SOUTHEAST THROUGH THE EVENING. HAVE SEEN A
HANDFUL OF SLEET REPORTS JUST TO OUR SOUTH/SOUTHWEST THANKS TO
EVAPORATIONAL COOLING IN ANTECEDENT MODIFIED CP AIRMASS.
ISENTROPIC UPGLIDE (290-300K SURFACES) RAMP UP QUICKLY LATE THIS
AFTERNOON AND THIS EVENING AS SSW MID-LEVEL FLOW INCREASES ACROSS
THE SOUTHEAST AND LOWER MID- ATLANTIC. THIS WILL SLOWLY SPREAD RAIN
NORTH-NORTHEAST OVER THE AREA TONIGHT. RUC SOUNDINGS DO ARGUE FOR
A BRIEF PERIOD OF SLEET ACROSS THE PIEDMONT, SOUTH CENTRAL VA/INTR
NE NC, QUICKLY BECOMING ALL RAIN AS WAA CONTINUES AND LLVLS BECOME
SATURATED. CONSIDERING ROAD TEMPS WELL ABOVE FREEZING, THIS SHOULD
BE A MINIMAL IMPACT, BUT NONETHELESS WORTH MENTIONING IN THE GOING
FORECAST.
THE MID-LEVEL TROUGH TRACKS OVER THE DEEP SOUTH TONIGHT...WITH
THE SURFACE LOW PRESSURE TRACKING NE OFF THE COAST ALONG THE
COASTAL BOUNDARY...WITH SOME ADDITIONAL NUDGING FROM THE NORTHERN
STREAM TROUGH. RATHER VIGOROUS VERTICAL ASCENT IS PROGGED TO MOVE
NE ACROSS THE LOCAL AREA BETWEEN 00-09Z...WHICH SHOULD BRING A
PERIOD OF MODERATE COLD RAIN TO MUCH OF THE AREA...CENTERED/HEAVIEST
FROM S-CENTRAL VA TO THE EASTERN SHORE. BRIEF WINDOW OF MAINLY
ELEVATED INSTABILITY ARRIVES AFTER MIDNIGHT. TOTAL TOTALS IN THE
LOW 50S, WITH ENOUGH VERTICAL ASCENT TO OVERCOME NEUTRAL LI
VALUES WOULD ARGUE FOR PERHAPS A RUMBLE OF THUNDER OR TWO ACROSS
THE FAR SOUTHEAST, SO HV ADDED A SLIGHT RISK FOR THUNDER AFTER
MIDNIGHT OVER FAR SE VA/NE NC. RAINFALL RATES SHOULD TAPER OFF
QUICKLY AS THE PRIMARY FORCING MOVES OFF THE COAST TOWARDS DAWN
FRIDAY MORNING. HOWEVER...LINGERING LOW-LEVEL MOISTURE SHOULD
ALLOW FOR STRATUS AND AREAS OF LIGHT RAIN/DRIZZLE. QPF AMOUNTS
RANGE FROM 0.5IN FAR NW...TO 1.25 ACROSS S-CENTRAL VA TO THE
COASTAL ZONES. LOWS SHOULD RANGE FROM THE M/U 30S NW...TO THE MID
40S SE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
LOW STRATUS AND AREAS OF LIGHT RA/DZ WILL LINGER FRIDAY MORNING,
BEFORE GRADUALLY CLEARING FROM NW TO SE AS WINDS BACK TO THE N-NW.
RAIN CHANCES ALSO DROP OFF QUICKLY AFTER 15Z AS MODEL CROSS
SECTIONS SHOW MID-LEVELS DRYING OUT QUICKLY. HIGHS SHOULD RANGE
FROM THE MID-UPPER 50S ALONG THE IMMEDIATE COAST...TO THE LOW 60S
INLAND.
HIGH PRESSURE BUILDS OVER THE AREA LATE FRIDAY NIGHT THROUGH
SATURDAY MORNING, BEFORE SLIDING OFFSHORE LATER SATURDAY.
QUASI-ZONAL/FLAT FLOW ALOFT ALLOWS DRIER AIR TO FILTER IN FROM THE
WEST FRIDAY AND SATURDAY. THUS, APART FROM SOME DIURNALLY DRIVEN
CUMULUS SATURDAY MORNING/AFTN, COURTESY OF ONSHORE (E-SE) LOW LEVEL
FLOW, EXPECT A MAINLY CLEAR SKY DURING THIS PERIOD. BY SUNDAY, FLOW
ALOFT OVER THE EASTERN THIRD OF THE COUNTRY BECOMES S-SW, AS UPPER
TROUGH COMES ASHORE THE PACIFIC COAST. THIS SHOULD EVENTUALLY LEAD
TO A WARM-UP BY LATE IN THE WEEKEND. CLEAR SKY/DRY AIRMASS SHOULD
BRING CHILLY EARLY MORNING SATURDAY AND SUNDAY MORNINGS. LOWS FROM
THE MID 30S N/NW TO LOW 40S SE COAST SAT MORNING...U30S TO MID 40S
SUNDAY MORNING. FORECAST HIGHS SAT RANGE FROM THE UPPER 40S/LOW
50S ALONG THE IMMEDIATE ATLANTIC COAST OF THE EASTERN SHORE TO
LOW 60S FROM THE I-95 CORRIDOR WEST. HIGHS WARM WELL INTO THE 60S
ON SUNDAY, WITH LOW 70S LIKELY WEST OF THE CHES BAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
12Z GFS/ECMWF IN GENERAL AGREEMENT SUN NGT INTO TUE MORNG...THEN
ARE QUITE DIFFERENT FOR TUE THRU THU. GFS MAINTAINS A WARMER
SCENARIO THRU THE PERIOD...KEEPING A FRNTL BOUNDARY N OF THE CWA
WITH AN UA RDG BLDNG OVR THE MID ATLC REGION TUE THRU WED...THEN
IT SLIDES OUT TO SEA WED NGT AND THU. WHILE...THE ECMWF KEEPS THE
FRNTL BOUNDARY NW OR N OF THE CWA SUN NGT INTO TUE MORNG...THEN
DROPS THE FRNT DOWN ACRS THE AREA TUE AFTN INTO WED...THEN
LINGERING THE FRNT NEAR THE VA/NC BORDER THRU THU. AT THIS TIME
GOING WITH THE WARMER GFS MODEL THRU THE PERIOD...WITH JUST A SLGT
OR SML CHC FOR SHOWERS POSSIBLE WED THRU THU. MAX TEMPS WILL RANGE
FM THE MID 60S TO MID 70S MON...AND IN THE UPR 60S TO UPR 70S TUE
THRU THU. MIN TEMPS WILL BE IN THE MID 40S TO LWR 50S MON
MORNG...AND MAINLY IN THE LWR TO MID 50S TUE...WED...AND THU
MORNGS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THIS AFTERNOON AS HIGH PRESSURE
RETREATS TO THE EAST. HIGH CLOUDS WILL CONTINUE TO OVERSPREAD THE
TAF SITES IN ADVANCE OF A LOW PRESSURE SYSTEM SLOWLY APPROACHING
FROM THE SW. CIGS BEGIN TO LOWER LATER THIS AFTERNOON AS THE LOW
MOVES NORTHWARD ALONG THE SE COAST. RAIN BEGINS BETWEEN 22Z/TODAY
AND 01Z/FRI THEN CONTINUES OVERNIGHT BEFORE TAPERING OFF AROUND
DAYBREAK FRIDAY. IFR CONDITIONS (MAINLY FOR CIGS) WILL BE LIKELY
TONIGHT AT ALL TAF SITES...WITH PERIODS OF MODERATE RAIN AS WELL.
LIFR CONDITIONS ARE POSSIBLE BUT NOT CONFIDENT ENUF TO INCLUDE IN
THE TAFS ATTM. HI PRES BLDS IN LATE FRI INTO THE WEEKEND LEADING
TO VFR CONDITIONS.
&&
.MARINE...
ESE THRU S FLO 5 TO 15 KTS EARLY THIS EVENG...WILL BECOME NE AND
INCREASE TO 15 TO 20 KTS TNGT...AS INTENSIFYING LO PRES MOVES FM
THE SE CST NNE TO JUST OFF THE MID ATLC CST BY 12Z FRI. THAT LO
WILL CONTINUE TO INTENSIFY DURING FRI...AS IT MOVES AWAY TO THE NE
AND HI PRES STARTS TO BLD IN FM THE NW. THE HI WILL MOVE TO RIGHT
OVR THE REGION SAT MORNG. THIS WILL RESULT IN STRONG N WNDS FM FRI
MORNG INTO SAT MORNG...WITH SCA`S FOR ALL WTRS EXCEPT THE RIVERS.
HI PRES WILL THEN SLIDE OFF THE CST FOR SUN THRU AT LEAST MON.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 7 PM EDT
FRIDAY FOR ANZ630>632-634.
SMALL CRAFT ADVISORY FROM 6 AM TO 7 PM EDT FRIDAY FOR ANZ633.
SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO NOON EDT SATURDAY FOR
ANZ652-654.
SMALL CRAFT ADVISORY FROM 1 AM FRIDAY TO NOON EDT SATURDAY FOR
ANZ656.
SMALL CRAFT ADVISORY FROM 6 AM FRIDAY TO NOON EDT SATURDAY FOR
ANZ650.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO NOON EDT
SATURDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MPR/MAM
SHORT TERM...MAM
LONG TERM...TMG
AVIATION...MAS
MARINE...TMG
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
450 PM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST FROM THE GULF COAST THROUGH TONIGHT.
THIS AREA OF LOW PRESSURE TRACKS ALONG THE SOUTHEAST COAST
OVERNIGHT BEFORE SLIDING OFF THE MID ATLANTIC COAST FRIDAY. HIGH
PRESSURE BUILDS OVER THE REGION SATURDAY AND SHIFTS OFFSHORE
SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
LATEST UPPER AIR ANALYSIS SHOWS A NORTHERN STREAM TROUGH TREKKING
ACROSS ONTARIO THIS AFTN, AS A SOUTHERN STREAM TROUGH IS NOW
ORIENTED OVER TEXARKANA/SOUTHERN MS VLY. AT THE SURFACE, WEAKENING
~1028MB SFC HIGH PRESSURE NOW ORIENTED JUST OFFSHORE, SETTING UP A
HYBRID COLD AIR DAMMING WEDGE STRUCTURE OVER THE REGION. TO THE
SOUTHWEST, A 1012MB LOW PRESSURE CENTER WAS CENTERED OVER THE FL
PANHANDLE...WITH INVERTED COASTAL TROUGH ANALYZED OFFSHORE OF THE
GA/SC COAST.
LOW PRESSURE OVER THE SOUTHEAST WILL LIFT NORTHEAST AS MS VLY
TROUGH WOBBLES EAST SOUTHEAST THROUGH THE EVENING. HAVE SEEN A
HANDFUL OF SLEET REPORTS JUST TO OUR SOUTH/SOUTHWEST THANKS TO
EVAPORATIONAL COOLING IN ANTECEDENT MODIFIED CP AIRMASS.
ISENTROPIC UPGLIDE (290-300K SURFACES) RAMP UP QUICKLY LATE THIS
AFTERNOON AND THIS EVENING AS SSW MID-LEVEL FLOW INCREASES ACROSS
THE SOUTHEAST AND LOWER MID- ATLANTIC. THIS WILL SLOWLY SPREAD RAIN
NORTH-NORTHEAST OVER THE AREA TONIGHT. RUC SOUNDINGS DO ARGUE FOR
A BRIEF PERIOD OF SLEET ACROSS THE PIEDMONT, SOUTH CENTRAL VA/INTR
NE NC, QUICKLY BECOMING ALL RAIN AS WAA CONTINUES AND LLVLS BECOME
SATURATED. CONSIDERING ROAD TEMPS WELL ABOVE FREEZING, THIS SHOULD
BE A MINIMAL IMPACT, BUT NONETHELESS WORTH MENTIONING IN THE GOING
FORECAST.
THE MID-LEVEL TROUGH TRACKS OVER THE DEEP SOUTH TONIGHT...WITH
THE SURFACE LOW PRESSURE TRACKING NE OFF THE COAST ALONG THE
COASTAL BOUNDARY...WITH SOME ADDITIONAL NUDGING FROM THE NORTHERN
STREAM TROUGH. RATHER VIGOROUS VERTICAL ASCENT IS PROGGED TO MOVE
NE ACROSS THE LOCAL AREA BETWEEN 00-09Z...WHICH SHOULD BRING A
PERIOD OF MODERATE COLD RAIN TO MUCH OF THE AREA...CENTERED/HEAVIEST
FROM S-CENTRAL VA TO THE EASTERN SHORE. BRIEF WINDOW OF MAINLY
ELEVATED INSTABILITY ARRIVES AFTER MIDNIGHT. TOTAL TOTALS IN THE
LOW 50S, WITH ENOUGH VERTICAL ASCENT TO OVERCOME NEUTRAL LI
VALUES WOULD ARGUE FOR PERHAPS A RUMBLE OF THUNDER OR TWO ACROSS
THE FAR SOUTHEAST, SO HV ADDED A SLIGHT RISK FOR THUNDER AFTER
MIDNIGHT OVER FAR SE VA/NE NC. RAINFALL RATES SHOULD TAPER OFF
QUICKLY AS THE PRIMARY FORCING MOVES OFF THE COAST TOWARDS DAWN
FRIDAY MORNING. HOWEVER...LINGERING LOW-LEVEL MOISTURE SHOULD
ALLOW FOR STRATUS AND AREAS OF LIGHT RAIN/DRIZZLE. QPF AMOUNTS
RANGE FROM 0.5IN FAR NW...TO 1.25 ACROSS S-CENTRAL VA TO THE
COASTAL ZONES. LOWS SHOULD RANGE FROM THE M/U 30S NW...TO THE MID
40S SE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
LOW STRATUS AND AREAS OF LIGHT RA/DZ WILL LINGER FRIDAY MORNING,
BEFORE GRADUALLY CLEARING FROM NW TO SE AS WINDS BACK TO THE N-NW.
RAIN CHANCES ALSO DROP OFF QUICKLY AFTER 15Z AS MODEL CROSS
SECTIONS SHOW MID-LEVELS DRYING OUT QUICKLY. HIGHS SHOULD RANGE
FROM THE MID-UPPER 50S ALONG THE IMMEDIATE COAST...TO THE LOW 60S
INLAND.
HIGH PRESSURE BUILDS OVER THE AREA LATE FRIDAY NIGHT THROUGH
SATURDAY MORNING, BEFORE SLIDING OFFSHORE LATER SATURDAY.
QUASI-ZONAL/FLAT FLOW ALOFT ALLOWS DRIER AIR TO FILTER IN FROM THE
WEST FRIDAY AND SATURDAY. THUS, APART FROM SOME DIURNALLY DRIVEN
CUMULUS SATURDAY MORNING/AFTN, COURTESY OF ONSHORE (E-SE) LOW LEVEL
FLOW, EXPECT A MAINLY CLEAR SKY DURING THIS PERIOD. BY SUNDAY, FLOW
ALOFT OVER THE EASTERN THIRD OF THE COUNTRY BECOMES S-SW, AS UPPER
TROUGH COMES ASHORE THE PACIFIC COAST. THIS SHOULD EVENTUALLY LEAD
TO A WARM-UP BY LATE IN THE WEEKEND. CLEAR SKY/DRY AIRMASS SHOULD
BRING CHILLY EARLY MORNING SATURDAY AND SUNDAY MORNINGS. LOWS FROM
THE MID 30S N/NW TO LOW 40S SE COAST SAT MORNING...U30S TO MID 40S
SUNDAY MORNING. FORECAST HIGHS SAT RANGE FROM THE UPPER 40S/LOW
50S ALONG THE IMMEDIATE ATLANTIC COAST OF THE EASTERN SHORE TO
LOW 60S FROM THE I-95 CORRIDOR WEST. HIGHS WARM WELL INTO THE 60S
ON SUNDAY, WITH LOW 70S LIKELY WEST OF THE CHES BAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
12Z GFS/ECMWF IN GENERAL AGREEMENT SUN NGT INTO TUE MORNG...THEN
ARE QUITE DIFFERENT FOR TUE THRU THU. GFS MAINTAINS A WARMER
SCENARIO THRU THE PERIOD...KEEPING A FRNTL BOUNDARY N OF THE CWA
WITH AN UA RDG BLDNG OVR THE MID ATLC REGION TUE THRU WED...THEN
IT SLIDES OUT TO SEA WED NGT AND THU. WHILE...THE ECMWF KEEPS THE
FRNTL BOUNDARY NW OR N OF THE CWA SUN NGT INTO TUE MORNG...THEN
DROPS THE FRNT DOWN ACRS THE AREA TUE AFTN INTO WED...THEN
LINGERING THE FRNT NEAR THE VA/NC BORDER THRU THU. AT THIS TIME
GOING WITH THE WARMER GFS MODEL THRU THE PERIOD...WITH JUST A SLGT
OR SML CHC FOR SHOWERS POSSIBLE WED THRU THU. MAX TEMPS WILL RANGE
FM THE MID 60S TO MID 70S MON...AND IN THE UPR 60S TO UPR 70S TUE
THRU THU. MIN TEMPS WILL BE IN THE MID 40S TO LWR 50S MON
MORNG...AND MAINLY IN THE LWR TO MID 50S TUE...WED...AND THU
MORNGS.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THIS AFTERNOON AS HIGH PRESSURE
RETREATS TO THE EAST. HIGH CLOUDS WILL CONTINUE TO OVERSPREAD THE
TAF SITES IN ADVANCE OF A LOW PRESSURE SYSTEM SLOWLY APPROACHING
FROM THE SW. CIGS BEGIN TO LOWER LATER THIS AFTERNOON AS THE LOW
MOVES NORTHWARD ALONG THE SE COAST. RAIN BEGINS BETWEEN 22Z/TODAY
AND 01Z/FRI THEN CONTINUES OVERNIGHT BEFORE TAPERING OFF AROUND
DAYBREAK FRIDAY. IFR CONDITIONS (MAINLY FOR CIGS) WILL BE LIKELY
TONIGHT AT ALL TAF SITES...WITH PERIODS OF MODERATE RAIN AS WELL.
LIFR CONDITIONS ARE POSSIBLE BUT NOT CONFIDENT ENUF TO INCLUDE IN
THE TAFS ATTM. HI PRES BLDS IN LATE FRI INTO THE WEEKEND LEADING
TO VFR CONDITIONS.
&&
.MARINE...
ESE THRU S FLO 5 TO 15 KTS EARLY THIS EVENG...WILL BECOME NE AND
INCREASE TO 15 TO 20 KTS TNGT...AS INTENSIFYING LO PRES MOVES FM
THE SE CST NNE TO JUST OFF THE MID ATLC CST BY 12Z FRI. THAT LO
WILL CONTINUE TO INTENSIFY DURING FRI...AS IT MOVES AWAY TO THE NE
AND HI PRES STARTS TO BLD IN FM THE NW. THE HI WILL MOVE TO RIGHT
OVR THE REGION SAT MORNG. THIS WILL RESULT IN STRONG N WNDS FM FRI
MORNG INTO SAT MORNG...WITH SCA`S FOR ALL WTRS EXCEPT THE RIVERS.
HI PRES WILL THEN SLIDE OFF THE CST FOR SUN THRU AT LEAST MON.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 7 PM EDT
FRIDAY FOR ANZ630>632-634.
SMALL CRAFT ADVISORY FROM 6 AM TO 7 PM EDT FRIDAY FOR ANZ633.
SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO NOON EDT SATURDAY FOR
ANZ652-654.
SMALL CRAFT ADVISORY FROM 1 AM FRIDAY TO NOON EDT SATURDAY FOR
ANZ656.
SMALL CRAFT ADVISORY FROM 6 AM FRIDAY TO NOON EDT SATURDAY FOR
ANZ650.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO NOON EDT
SATURDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...AJZ/MAM
SHORT TERM...MAM
LONG TERM...TMG
AVIATION...MAS
MARINE...TMG
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
410 PM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST FROM THE GULF COAST THROUGH TONIGHT.
THIS AREA OF LOW PRESSURE TRACKS ALONG THE SOUTHEAST COAST
OVERNIGHT BEFORE SLIDING OFF THE MID ATLANTIC COAST FRIDAY. HIGH
PRESSURE BUILDS OVER THE REGION SATURDAY AND SHIFTS OFFSHORE
SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
LATEST UPPER AIR ANALYSIS SHOWS A NORTHERN STREAM TROUGH TREKKING
ACROSS ONTARIO THIS AFTN, AS A SOUTHERN STREAM TROUGH IS NOW
ORIENTED OVER TEXARKANA/SOUTHERN MS VLY. AT THE SURFACE, WEAKENING
~1028MB SFC HIGH PRESSURE NOW ORIENTED JUST OFFSHORE, SETTING UP A
HYBRID COLD AIR DAMMING WEDGE STRUCTURE OVER THE REGION. TO THE
SOUTHWEST, A 1012MB LOW PRESSURE CENTER WAS CENTERED OVER THE FL
PANHANDLE...WITH INVERTED COASTAL TROUGH ANALYZED OFFSHORE OF THE
GA/SC COAST.
LOW PRESSURE OVER THE SOUTHEAST WILL LIFT NORTHEAST AS MS VLY
TROUGH WOBBLES EAST SOUTHEAST THROUGH THE EVENING. HAVE SEEN A
HANDFUL OF SLEET REPORTS JUST TO OUR SOUTH/SOUTHWEST THANKS TO
EVAPORATIONAL COOLING IN ANTECEDENT MODIFIED CP AIRMASS.
ISENTROPIC UPGLIDE (290-300K SURFACES) RAMP UP QUICKLY LATE THIS
AFTERNOON AND THIS EVENING AS SSW MID-LEVEL FLOW INCREASES ACROSS
THE SOUTHEAST AND LOWER MID- ATLANTIC. THIS WILL SLOWLY SPREAD RAIN
NORTH-NORTHEAST OVER THE AREA TONIGHT. RUC SOUNDINGS DO ARGUE FOR
A BRIEF PERIOD OF SLEET ACROSS THE PIEDMONT, SOUTH CENTRAL VA/INTR
NE NC, QUICKLY BECOMING ALL RAIN AS WAA CONTINUES AND LLVLS BECOME
SATURATED. CONSIDERING ROAD TEMPS WELL ABOVE FREEZING, THIS SHOULD
BE A MINIMAL IMPACT, BUT NONETHELESS WORTH MENTIONING IN THE GOING
FORECAST.
THE MID-LEVEL TROUGH TRACKS OVER THE DEEP SOUTH TONIGHT...WITH
THE SURFACE LOW PRESSURE TRACKING NE OFF THE COAST ALONG THE
COASTAL BOUNDARY...WITH SOME ADDITIONAL NUDGING FROM THE NORTHERN
STREAM TROUGH. RATHER VIGOROUS VERTICAL ASCENT IS PROGGED TO MOVE
NE ACROSS THE LOCAL AREA BETWEEN 00-09Z...WHICH SHOULD BRING A
PERIOD OF MODERATE COLD RAIN TO MUCH OF THE AREA...CENTERED/HEAVIEST
FROM S-CENTRAL VA TO THE EASTERN SHORE. BRIEF WINDOW OF MAINLY
ELEVATED INSTABILITY ARRIVES AFTER MIDNIGHT. TOTAL TOTALS IN THE
LOW 50S, WITH ENOUGH VERTICAL ASCENT TO OVERCOME NEUTRAL LI
VALUES WOULD ARGUE FOR PERHAPS A RUMBLE OF THUNDER OR TWO ACROSS
THE FAR SOUTHEAST, SO HV ADDED A SLIGHT RISK FOR THUNDER AFTER
MIDNIGHT OVER FAR SE VA/NE NC. RAINFALL RATES SHOULD TAPER OFF
QUICKLY AS THE PRIMARY FORCING MOVES OFF THE COAST TOWARDS DAWN
FRIDAY MORNING. HOWEVER...LINGERING LOW-LEVEL MOISTURE SHOULD
ALLOW FOR STRATUS AND AREAS OF LIGHT RAIN/DRIZZLE. QPF AMOUNTS
RANGE FROM 0.5IN FAR NW...TO 1.25 ACROSS S-CENTRAL VA TO THE
COASTAL ZONES. LOWS SHOULD RANGE FROM THE M/U 30S NW...TO THE MID
40S SE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
LOW STRATUS AND AREAS OF LIGHT RA/DZ WILL LINGER FRIDAY MORNING,
BEFORE GRADUALLY CLEARING FROM NW TO SE AS WINDS BACK TO THE N-NW.
RAIN CHANCES ALSO DROP OFF QUICKLY AFTER 15Z AS MODEL CROSS
SECTIONS SHOW MID-LEVELS DRYING OUT QUICKLY. HIGHS SHOULD RANGE
FROM THE MID-UPPER 50S ALONG THE IMMEDIATE COAST...TO THE LOW 60S
INLAND.
HIGH PRESSURE BUILDS OVER THE AREA LATE FRIDAY NIGHT THROUGH
SATURDAY MORNING, BEFORE SLIDING OFFSHORE LATER SATURDAY.
QUASI-ZONAL/FLAT FLOW ALOFT ALLOWS DRIER AIR TO FILTER IN FROM THE
WEST FRIDAY AND SATURDAY. THUS, APART FROM SOME DIURNALLY DRIVEN
CUMULUS SATURDAY MORNING/AFTN, COURTESY OF ONSHORE (E-SE) LOW LEVEL
FLOW, EXPECT A MAINLY CLEAR SKY DURING THIS PERIOD. BY SUNDAY, FLOW
ALOFT OVER THE EASTERN THIRD OF THE COUNTRY BECOMES S-SW, AS UPPER
TROUGH COMES ASHORE THE PACIFIC COAST. THIS SHOULD EVENTUALLY LEAD
TO A WARM-UP BY LATE IN THE WEEKEND. CLEAR SKY/DRY AIRMASS SHOULD
BRING CHILLY EARLY MORNING SATURDAY AND SUNDAY MORNINGS. LOWS FROM
THE MID 30S N/NW TO LOW 40S SE COAST SAT MORNING...U30S TO MID 40S
SUNDAY MORNING. FORECAST HIGHS SAT RANGE FROM THE UPPER 40S/LOW
50S ALONG THE IMMEDIATE ATLANTIC COAST OF THE EASTERN SHORE TO
LOW 60S FROM THE I-95 CORRIDOR WEST. HIGHS WARM WELL INTO THE 60S
ON SUNDAY, WITH LOW 70S LIKELY WEST OF THE CHES BAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
12Z GFS/ECMWF IN GENERAL AGREEMENT SAT NGT INTO MON NGT...THEN
DIFFER TUE THRU WED WITH REGARD TO A BACKDOOR FRONT...WHICH THE
ECMWF BRINGS DOWN INTO AND ACRS THE CWA TUE AFTN THRU WED. THE GFS
BLDS THE UA RDG OVR THE MID ATLC REGION AND OFF THE CST DURING
THIS TIME PERIOD. AT THIS TIME...LEANING TWD THE WARMER AND DRIER
GFS THRU THE PERIOD...WITH ONLY A SLGT CHC OF SHOWERS FOR WED. SFC
HI PRES WILL SLIDE OFF THE MID ATLC CST SAT NGT AND SUN...THEN
MOVE FARTHER OUT TO SEA DURING WED. MAX TEMPS WILL RANGE THRU THE
60S SUN...THEN GENERALLY RANGE FM THE MID 60S TO MID 70S MON THRU
WED. MIN TEMPS WILL BE IN THE MID 30S TO ARND 40 SUN MORNG...IN
THE MID 40S TO ARND 50 MON MORNG...IN THE UPR 40S TO LWR 50S TUE
MORNG...AND IN THE LWR TO MID 50S WED MORNG.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THIS AFTERNOON AS HIGH PRESSURE
RETREATS TO THE EAST. HIGH CLOUDS WILL CONTINUE TO OVERSPREAD THE
TAF SITES IN ADVANCE OF A LOW PRESSURE SYSTEM SLOWLY APPROACHING
FROM THE SW. CIGS BEGIN TO LOWER LATER THIS AFTERNOON AS THE LOW
MOVES NORTHWARD ALONG THE SE COAST. RAIN BEGINS BETWEEN 22Z/TODAY
AND 01Z/FRI THEN CONTINUES OVERNIGHT BEFORE TAPERING OFF AROUND
DAYBREAK FRIDAY. IFR CONDITIONS (MAINLY FOR CIGS) WILL BE LIKELY
TONIGHT AT ALL TAF SITES...WITH PERIODS OF MODERATE RAIN AS WELL.
LIFR CONDITIONS ARE POSSIBLE BUT NOT CONFIDENT ENUF TO INCLUDE IN
THE TAFS ATTM. HI PRES BLDS IN LATE FRI INTO THE WEEKEND LEADING
TO VFR CONDITIONS.
&&
.MARINE...
LIGHT NE FLOW THIS MORNING BECOMES E AND SE THIS AFTERNOON AS HIGH
PRESSURE SLIDES OFF THE CST...FOLLOWED BY INTENSIFYING LOW PRESSURE
TRACKING FROM THE GULF COAST STATES NE UP AND OFF THE MID ATLC CST
THIS EVENING THRU FRIDAY MORNING. SOLID SCA CONDITIONS ARE EXPECTED
TO DEVELOP ON THE COASTAL WATERS TONIGHT AS THE LOW INTENSIFIES AND
SEAS BUILD TO AT LEAST 5-8 FT. WIND GUSTS TO 30 KT WILL ALSO BE
POSSIBLE ON FRIDAY. ON THE CHESAPEAKE BAY...WINDS INCREASE TO SCA
LEVELS THIS EVENING AND CONTINUE THRU FRIDAY. HAVE ACCORDINGLY
HOISTED SCA HEADLINES FOR THE BAY AND COASTAL WATERS BEGINNING THIS
EVENING. BECAUSE OF HIGH CONFIDENCE IN SEAS REMAINING ELEVATED THRU
AT LEAST FRI NIGHT...HAVE THE SCA`S FOR THE COASTAL WATERS CONTINUING
THROUGH 6 AM SAT. CONFIDENCE NOT HIGH ENOUGH ATTM TO ISSUE ANY SCA
HEADLINES ON THE CURRITUCK SOUND AND THE EASTERN VA RIVERS...SO WILL
LET DAY SHIFT RE-EVALUATE AND ISSUE AS NECESSARY. HIGH PRES WILL
BUILD BACK OVR THE REGION FOR SATURDAY...THEN SLIDES OFF THE COAST
FOR SUN AND MON.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 7 PM EDT
FRIDAY FOR ANZ630>632-634.
SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ652-654.
SMALL CRAFT ADVISORY FROM 1 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ656.
SMALL CRAFT ADVISORY FROM 6 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ650.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EDT
SATURDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...AJZ/MAM
SHORT TERM...MAM
LONG TERM...TMG
AVIATION...JDM/MAS
MARINE...TMG
AREA FORECAST DISCUSSION
NWS GAYLORD MI
347 PM EDT THU APR 4 2013
.SYNOPSIS...
ISSUED AT 344 PM EDT THU APR 4 2013
A COLD FRONT IS MOVING THROUGH NORTHERN MICHIGAN...BRINGING A
PERIOD OF LIGHT RAIN AND SNOW FOR THIS AFTERNOON AND TONIGHT.
SETTLED WEATHER WILL RETURN FOR A SHORT TIME ON FRIDAY...BEFORE
ANOTHER STORM SYSTEM MOVES INTO NORTHERN MICHIGAN...BRINGING RAIN
AND SNOW MIXED FOR SATURDAY INTO SUNDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
THE CURRENT RADAR SHOWS A NARROW BAND OF PCPN SLOWLY DROPPING SOUTH
ACROSS NORTHERN LOWER MICHIGAN. THIS NARROW AREA OF PRECIPITATION IS
THE RESULT OF A COLD FRONT SINKING SOUTH OVER THE REGION. VIS SAT
AND SFC OBS SHOW LIMITED MOISTURE EITHER SIDE OF THE BOUNDARY...WITH
MOSTLY SUNNY SKIES OVER MUCH OF CENTRAL AND SOUTHERN MICHIGAN. SUN
OVER THE SRN CWA FROM EARLIER TODAY...HAS ALLOWED AFTERNOON TEMPS IN
THESE AREAS TO WARM QUICKLY INTO THE MID AND UPPER 40S...WHILE
TEMPS REMAIN IN THE 30S OVER ERN UPPER NORTH OF THE BOUNDARY.
OVERALL THE MAIN FORECAST CONCERNS TONIGHT THROUGH FRIDAY WILL BE
TIMING AND TYPE OF PCPN TONIGHT WITH THE APPROACHING FRONT...ALONG
WITH ANY LAKE INDUCED SNOWS FRIDAY ON THE BACKSIDE OF THE COLD
FRONT.
THE STORM SYSTEM CURRENTLY MOVING ACRS ONTARIO WILL QUICKLY EXIT
INTO QUEBEC THIS EVENING. A COLD FRONT ASSOCIATED WITH THIS SYSTEM...
WILL CONT TO DROP SOUTH ACRS NRN LWR MI THIS EVENING BEFORE EXITING
EAST. EXPECT THE FRONT TO HAVE CLEARED NORTHERN LOWER MICHIGAN
BTWN 03Z AND 06Z. THE ONLY PCPN ASSOCIATED WITH THIS BOUNDARY HAS
BEEN LOCATED RIGHT ALONG THE FRONT...DUE TO THE EXTREMELY DRY AIR
LOCATED OVER THE GREAT LAKES. HOWEVER SFC DEW PTS EVENTUALLY
INCREASED FROM THE TEENS INTO THE MID 20S OVER THE STRAITS AS THE
FRONT APPROACHED (ENOUGH TO GENERATE PCPN). HOWEVER PCPN TYPE AND
CHC OVER THE REST OF THE CWA WILL BE DIFFICULT THIS EVENING AS THE
FRONT DIPS SOUTH. TO THIS POINT...ALL OF THE PCPN HAS BEEN IN THE
FORM OF SNOW OVER ERN UPPER AND THE STRAITS. THE LATEST RUC MODEL
SOUNDINGS SHOW AN INVERTED V SIGNATURE IN THE LOWEST LAYERS FROM
GAYLORD SOUTH TO THE SAGINAW BAY THIS EVENING...WITH OTHERWISE
EXTREMELY DRY AIR ABOVE 850MB. ADDING COMPLICATIONS TO PCPN TYPE
THIS EVENING IS THE VERTICAL TEMP PROFILES...AS MOST OF NRN LWR
WARMED WELL INTO THE MID AND UPPER 40S DUE TO SOUTHWEST WINDS AND
FULL SUN IN ADVANCE OF THE FRONT. HOWEVER PROGGED 850MB WET BULB TEMPS
WOULD SUGGEST ENOUGH EVAP COOLING WITH ONSET OF ADVANCING MSTR TO AT
LEAST MENTION A RAIN/SNOW MIX. OVERALL WILL CONTINUE THE LATEST
TREND OF CHC POPS RAIN/SNOW MIXED OVER THE SRN HALF OF THE CWA AND
SAGINAW BAY INTO THIS EVENING.
COLDER AIR AND NORTHWEST FLOW RE-SETTLES INTO THE REGION OVERNIGHT
AND FRIDAY ON THE BACK SIDE OF THE EXITING BOUNDARY. 850MB TEMPS
QUICKLY DROP FROM ARND -4C THIS EVENING TO BETWEEN -12C AND -14C BY
12Z FRIDAY. SFC-850MB WINDS TURN FROM THE SOUTHWEST THIS EVENING IN
ADVANCE OF THE BOUNDARY TO NNW FRIDAY. MODEL SOUNDINGS SUGGEST INVERSION
HEIGHTS INCREASING TO NEAR 5K FT WHILE LINGERING LOW LVL MSTR EXTENDS
TO AROUND THE -12C ISOTHERM. OVERALL MENTION CHC POPS IN NORTH FLOW
SNOW BELTS EARLY FRIDAY. OTHERWISE WILL MENTION AT LEAST PARTLY
SUNNY SKIES OVER THE REST OF THE CWA FRIDAY. WILL MENTION COOLER AFTN
TEMPS FRIDAY...RANGING FROM AROUND FREEZING OVER ERN UPPER AND THE
STRAITS TO THE LOWER 40S NEAR SAGINAW BAY.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 344 PM EDT THU APR 4 2013
LITTLE CHANGE FROM WHAT WAS SEEN YESTERDAY...WITH STILL PLENTY OF
POTENTIAL FOR A VERY ACTIVE NEXT 7 DAYS OF WEATHER AS PERSISTENT
-AO RELAXES AND DEEP SOUTHWEST MOISTURE RICH FLOW DEVELOPS ON
FRONTSIDE OF DIGGING INTERMOUNTAIN WEST ENERGY. BIG WILD CARD
REMAINS POTENTIAL INTERACTION WITH POLAR LOW SET TO ROTATE ACROSS
EASTERN CANADA. EVENTUAL PLACEMENT OF THIS FEATURE WILL BE KEY IN
DETERMINING LOCATION OF INTENSE LOW LEVEL THERMAL BOUNDARY AND
SUBSEQUENT PATHWAY FOR ENERGY ROTATING OUT OF WESTERN TROUGH AXIS.
WHILE ABOVE REMAINS A VERY LOW CONFIDENCE PORTION OF THE
FORECAST...LEAD WAVE APPROACHING THE PACIFIC NORTHWEST (NICELY
ILLUSTRATED ON LATEST WATER VAPOR IMAGERY) NOW WELL AGREED UPON TO
IMPACT OUR WEATHER INTO THE START OF THIS WEEKEND. THIS WAVE WILL
BRING ANOTHER BOUT OF WINTRY WEATHER TO THE NORTH WOODS
SATURDAY...WITH INCREASING CONFIDENCE PARTS OF EASTERN UPPER WILL
SEE A PERIOD OF ACCUMULATING SNOW. FORECAST CONCERNS INITIALLY
DEAL WITH THIS LATTER SYSTEM...SPECIFICALLY SNOWFALL ACCUMULATIONS
FOR EASTERN UPPER. MUCH MORE OF PROBABILISTIC APPROACH TAKING FOR
THE REMAINDER OF THE FORECAST...WITH AT LEAST SOME ATTEMPT AT
ADDRESSING MULTI- PERIOD PRECIP CHANCES AND TEMPERATURE TRENDS.
GUIDANCE HAS LOCKED IN A SOLUTION SENDING PACIFIC NORTHWEST WAVE
RAPIDLY EAST INTO THE NORTHERN PLAIN FRIDAY NIGHT...AND THROUGH
NORTHERN MICHIGAN BY SATURDAY NIGHT. WEAKISH COUPLED JET STRUCTURE
AND LOW LEVEL THERMAL BOUNDARY EXPECTED TO ENTICE RESPECTABLE
SURFACE LOW PRESSURE DEVELOPMENT WITH THIS MID LEVEL WAVE...ITSELF
EXPECTED TO SLICE THROUGH THE HEART OF NORTHERN LOWER MICHIGAN
SATURDAY EVENING. ALTHOUGH WAVE ITSELF AND SURFACE FEATURE NOTHING
TO WRITE HOME ABOUT...ACCOMPANYING DYNAMICS REMAIN IMPRESSIVE INDEED.
MULTI-PERIOD TRENDS CONTINUE TO SUPPORT AGGRESSIVE WAA DRIVEN
DYNAMICS...WITH NEAR 60 KNOT SOUTHWEST FLOW LOW LEVEL JET
PERPENDICULAR TO THE 290K-295K PRESSURE SURFACES. DEEP LAYER FGEN
SIGNAL ALSO PRESENT ALONG RETREATING COLD DOME...COLLOCATED NICELY
WITH MAX WAA UPGLIDE ON NOSE OF LOW LEVEL JET. BEST JUXTAPOSITION OF
THE ABOVE EXPECTED ACROSS FAR NORTHERN LOWER AND AREAS NORTH OF THE
BRIDGE SATURDAY INTO SATURDAY EVENING. SYSTEM HAS A NICE SUBTROPICAL
PACIFIC MOISTURE PLUME ALREADY ASSOCIATED WITH IT...SOME OF WHICH
WILL BE ADVECTED INTO OUR AREA AS SYSTEM APPROACHES. COMBINE THIS
WITH BRIEF WINDOW FOR SOME WESTERN GULF OF MEXICO MOISTURE
CONTRIBUTION...AND PWAT VALUES SURGE TO AOA 0.75 INCHES LEVELS BY
LATER SATURDAY. SAID ISENTROPIC SURFACES ALSO SHOW VERY RESPECTABLE
MOISTURE...WITH MIXING RATIOS EXCEEDING 4 G/KG. LITTLE DOUBT SYSTEM
HAS ALL THE EARMARKS TO BE A RATHER SUBSTANTIAL PRECIP PRODUCER...
ALTHOUGH EXACTLY WHAT TYPE THAT PRECIP TAKES REMAINS A FORMIDABLE
CHALLENGE. WILL USE ROCK-STEADY ECMWF DEPICTIONS FOR THERMAL FIELDS.
THIS CONTINUES TO SUGGEST MAINLY SNOW AT THE ONSET EARLY
SATURDAY...RAPIDLY CHANGING OVER TO LIQUID FROM SOUTHWEST TO
NORTHEAST ACROSS NORTHERN LOWER MICHIGAN DURING THE MORNING. COULD
SEE SOME MINOR SNOW ACCUMULATIONS...ON THE ORDER OF AN INCH OR
SO...ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. WILL NEED TO WATCH
FOR A PERIOD OF FREEZING RAIN AS WAA STRENGTHENS JUST OFF THE DECK.
THIS SHOULD BE SHORT-LIVED EVENT (IF IT OCCURS AT ALL) AND NOT
WORTHY OF A MENTION IN THE FORECAST. MUCH BIGGER PRECIP TYPE
CHALLENGE ACROSS EASTERN UPPER...WITH STRONG DYNAMICS POSSIBLY
OVERCOMING MARGINAL THERMAL PROFILES TO KEEP PRECIP MAINLY ALL
SNOW...ESPECIALLY ALONG AND NORTH OF M-28. MODEL QPF FIELDS SOMEWHAT
DISCONCERTING...WITH PROGS SUPPORTING A HALF INCH OR MORE OF LIQUID
EQUIVALENT PRECIP BY LATER SATURDAY NIGHT. HEAVIER AMOUNTS NO DOUBT
POSSIBLE GIVEN AMOUNT OF EARLIER MENTIONED DYNAMICS. SNOW RATIOS
WILL NOT BE GREAT...ESPECIALLY SATURDAY AFTERNOON...WHEN SURFACE
READINGS WILL LIKELY EXCEED FREEZING AND HIGH APRIL SUN ANGLE TAKES
HOLD. STILL...COULD EASILY SEE SEVERAL INCHES OF HEAVY WET SNOW
ACCUMULATION BY LATER SATURDAY NIGHT...WITH PERIODS OF HIGH
INTENSITY SNOWFALL. NO HEADLINES FORTHCOMING ON THIS SHIFT...BUT IF
ABOVE COMES TO FRUITION...COULD SEE ADVISORY LEVEL SNOW AMOUNTS FOR
AT LEAST PARTS OF EASTERN UPPER. STAY TUNED! SYSTEM WINDS DOWN
QUICKLY LATE SATURDAY NIGHT...LEAVING BEHIND A DRY SUNDAY AND SUNDAY
EVENING.
CONFIDENCE DROPS REMARKABLY HEADING THROUGH NEXT WORK WEEK...WITH
GUIDANCE STRUGGLING WITH KEY INTERACTIONS TALKED ABOUT IN THE LEAD
PARAGRAPH. PLENTY OF POTENTIAL FOR ADDITIONAL SIGNIFICANT
SYSTEMS...WITH SOME DECENT SUPPORT FOR ONE SUCH SYSTEM TO IMPACT OUR
AREA TO KICK OFF THE WEEK. EXACTLY HOW FAR NORTH THIS SYSTEM RIDES UP
THROUGH THE OHIO VALLEY/SOUTHERN LAKES STILL FAR FROM BEING
DETERMINED. DEPENDING ON SUCH...MAY SEE ENOUGH COLD AIR ALONG THE
NORTHERN PERIPHERY OF ITS PRECIP SHIELD TO SUPPORT SOME WINTRY
WEATHER. NO NEED TO GET TOO SPECIFIC...AND WILL BE FORCED TO RUN
WITH A GUIDANCE CONSENSUS BLEND UNTIL A MORE DETERMINISTIC APPROACH
CAN BE UTILIZED. SAME STORY HEADING THROUGH THE REMAINDER OF THE
WEEK...WITH AGAIN THE POTENTIAL FOR ANOTHER WAVE TO ROTATE NORTHEAST
OUT OF THE SOUTHERN PLAINS. TIMING AND PLACEMENT OF SUCH ALL OVER
THE BOARD...AS IT WILL LIKELY REMAIN WITH BAROCLINIC AXIS SUBJECT TO
MANY CHANGES PER CANADIAN TROUGHING AND PASSAGE OF EARLIER IN THE
WEEK SYSTEMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 156 PM EDT THU APR 4 2013
VFR CIGS AND VSBY IN ADVANCE OF A FRONTAL BOUNDARY DROPPING SOUTH ACRS
NRN LWR MI...WILL TREND MVFR AND OCCASIONALLY IFR IN MIXED RAIN
AND SNOW THROUGH BTWN 00Z AND 03Z. COLDER AIR AND NORTHWEST WINDS
ON THE BACK SIDE OF THE EXITING SYSTEM...WILL GENERATE SOME LAKE
SNOWS OVER TAF SITE KTVC AND KMBL FRIDAY. GUSTY SOUTHWEST WINDS IN
ADVANCE OF THE BOUNDARY...WILL TREND NORTHWEST ACRS NRN LWR MI TAF
SITES BTWN 00Z AND 06Z.
&&
.MARINE...
ISSUED AT 344 PM EDT THU APR 4 2013
GUSTY SOUTHWEST WINDS IN ADVANCE OF A FRONTAL BOUNDARY DROPPING
SOUTH OVER NRN MI...WILL TURN NORTHWEST OVERNIGHT AND REMAIN BREEZY
ON THE BACKSIDE OF THE EXITING BOUNDARY. RAIN/SNOW MIXED PCPN WILL
AFFECT NRN MI NEARSHORE WATERS THIS EVENING AS BOUNDARY DROPS
SOUTH...WITH SOME LAKE SNOWS POSSIBLE FRIDAY BEHIND THE FRONT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-345-
346.
GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ341-342-344.
LS...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ321-322.
&&
$$
SYNOPSIS...KAB
SHORT TERM...SWR
LONG TERM...MSB
AVIATION...SWR
MARINE...SWR
AREA FORECAST DISCUSSION
NWS GAYLORD MI
158 PM EDT THU APR 4 2013
.SYNOPSIS...
ISSUED AT 420 AM EDT THU APR 4 2013
A COLD FRONT WILL MOVE THROUGH NORTHERN MICHIGAN TODAY.
PRECIPITATION ASSOCIATED WITH THIS FRONT WILL START AS SNOW THIS
MORNING...BUT MIX WITH RAIN AS THE TEMPERATURES RISE ABOVE
FREEZING TODAY. THE RAIN WILL END IN THE AFTERNOON AS DRIER TAKES
OVER BEFORE THE FRONT MOVES THROUGH. HIGH PRESSURE AND COOLER
TEMPERATURES WILL SETTLE IN FOR THURSDAY NIGHT AND FRIDAY BEFORE A
STORM SYSTEM MOVES INTO NORTHERN MICHIGAN AND HANGS AROUND FOR
MUCH OF THE WEEKEND...BRINGING RAIN AND SNOW MIXED FOR SATURDAY
AND SUNDAY.
&&
.UPDATE...
ISSUED AT 156 PM EDT THU APR 4 2013
THE CURRENT FORECAST IS IN LINE...AS A FRONTAL BOUNDARY CONTINUES
TO DROP SOUTH ACRS NRN LWR MI.
UPDATE ISSUED AT 933 AM EDT THU APR 4 2013
CURRENT RADAR AND SFC OBS SHOWING AREA OF PCPN OVER ERN UPPER AND
STRAITS REGION...WHICH IS IN RESPONSE TO A COLD FRONT PUSHING INTO
THE WRN LAKES. PCPN ASSOCIATED WITH THIS FRONT SO FAR THIS MORNING
HAS BEEN CONFINED TO A NARROW BAND...HINDERED GREATLY BY LIMITED
MSTR. SFC DEW PTS SOUTH OF THE STRAITS ARE CURRENTLY IN THE
TEENS...THOUGH DEW PTS HAVE INCREASED INTO THE LOWER AND MID 20 OVER
ERN UPPER JUST IN ADVANCE OF THE FRONT.
AS FOR THE REST OF TODAY...LIMITED MSTR WILL REMAIN A HINDRANCE
THROUGH THE AFTERNOON OVR NRN LWR MI...KEEPING ANY PCPN CONFINED TO
A NARROW AREA RIGHT ALONG THE FRONT. MODEL SOUNDINGS SHOW PCPN CHCS
ENDING FROM GLR NORTH BTWN 18Z AND 21Z...AND ENDING NEAR SAGINAW BAY
REGION BETWEEN 00Z AND 03Z.
OVERALL CURRENT FCST IN LINE WITH MILD TEMP AND SUN EARLY OVER THE
SRN CWA...WITH PCPN ENDING OVER ERN UPPER EARLY THIS AFTN.
UPDATE ISSUED AT 607 AM EDT THU APR 4 2013
CHANGES THIS HOUR: HAVE CONTINUED SLOWING TREND OF POPS THROUGH
MUCH OF TODAY GIVEN RECENT GOOD AGREEMENT BETWEEN THE NAM/RAP/HRRR
GIVEN VERY IMPRESSIVE PERFORMANCE FROM THE RAP OVER THE PAST FEW
HOURS. SNOWFALL HAS ARRIVED FROM SAW-ERY-ANJ AND WILL GO AHEAD AND
BUMP UP NEAR TERM POPS TO CATEGORICAL FOR NORTHERN CHIPPEWA
THROUGH DAYBREAK. BEYOND THIS...INITIAL SURGE OF ISENTROPIC ASCENT
ALONG LLEVEL MOISTURE AXIS WILL SHIFT EAST AND WE/LL THEN AWAIT
FURTHER DEVELOPMENT ALONG THE FRONTAL BOUNDARY ITSELF...WHICH IS
NOW SLIDING SOUTHEAST THROUGH WESTERN UPPER. DON/T EXPECT THIS TO
BE SUBSTANTIAL...AND AS PREVIOUSLY MENTIONED...EXPECT IT TO
DWINDLE AS IT HEADS SOUTH...WITH RAIN GRADUALLY TAKING OVER AS THE
PREDOMINATE PRECIPITATION TYPE.
COULD SEE AN INCH OF MORNING ACCUMS FROM PARADISE TO ANJ /WEBCAMS
SHOW A COATING ATTM/...SO WATCH OUT FOR SOME SLICK AM TRAVEL IN
THESE SPOTS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 420 AM EDT THU APR 4 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WINDS OVER MUCH OF
NORTHERN LAKE MICHIGAN THROUGH MID MORNING. WILL LIKELY HAVE SOME
COASTAL WIND GUSTS ABOVE 30 MPH TODAY...OTHERWISE...NO HIGH
IMPACT WEATHER EXPECTED.
OVERVIEW: SURFACE MAP EARLY THIS MORNING REVEALS HIGH PRESSURE
RESPONSIBLE FOR THE BEAUTIFUL /ALBEIT CHILLY/ AFTERNOON YESTERDAY
HAVING PUSHED SOUTH AND EAST INTO THE OHIO VALLEY/MID ATLANTIC
REGION...THIS HAS ALLOWED BROAD SOUTHWESTERLY FLOW TO DEVELOP BETWEEN
THIS FEATURE AND RATHER IMPRESSIVE SURFACE LOW NOW TRAVELING FROM
WEST TO EAST ACROSS NORTHERN ONTARIO. PRIMARY FEATURE OF NOTE
THROUGH THE SHORT TERM PORTION OF THE FORECAST IS A COLD FRONT
DRAPED TO THE SOUTH AND WEST OF THIS LOW...APPROACHING LAKE SUPERIOR
AS OF THIS WRITING. STRENGTHENING SOUTHWESTERLY WINDS OVER NORTHERN
MICHIGAN HAVE PRECLUDED STEEP TEMPERATURE FALLS OVERNIGHT WITH MOST
LOCATIONS AT LEAST 10F WARMER THAN 24 HOURS AGO. LLEVEL MOISTURE
HAS NOT RESPONDED IN TANDEM...WITH 00Z APX RAOB SHOWING A PALTRY
0.14" PWAT. CLOSER TO THE FRONT...HOWEVER...PRECIPITATION ECHOES
HAVE BEEN BLOSSOMING OVER THE PAST COUPLE OF HOURS AS ROBUST LOW
LEVEL JET AT H8 /50KTS+/ TRANSPORTS A PLUME OF 2/3" PWATS RAPIDLY
EASTWARD.
THROUGH DAYBREAK: WINDS CONTINUE TO RAMP UP FROM WEST TO EAST...WITH
SLOWLY INCREASING MID AND UPPER LEVEL CLOUDINESS...PRIMARILY FROM THE
STRAITS NORTH. TIMING AREA OF INCREASING RADAR ECHOES SUGGESTS
PRECIPITATION COULD ARRIVE AS EARLY AS 5-6AM OVER EASTERN UPPER AS
SOME SNOW SHOWERS. INTERESTING TO NOTE SURFACE DEWPOINT TREND OVER
THE PAST FEW HOURS OVER NORTHERN LOWER...WITH VALUES PLUMMETING TO
BELOW 10F AT TVC/CAD AND ROPPING EVERYWHERE AWAY FROM LAKE
MICHIGAN. THIS SUGGESTS THE SLOWING TREND IN FRONTAL PRECIP
ARRIVAL /SEEN IN RECENT RENDTIONS OF THE HRRR/RAP/ ARE LIKELY ON
THE RIGHT TRACK.
TODAY: COLD FRONT PUSHES THROUGH NORTHERN MICHIGAN TODAY...STARTING
THE DAY OVER WESTERN UPPER AND REACHING MY SOUTHEASTERN ZONES BY
EVENING. PRIMARY CONCERNS TODAY CENTER AROUND PRECIPITATION
CHANCES AS THIS BOUNDARY MOVES THROUGH...AS WELL AS THE STRENGTH
OF SOUTHWESTERLY WINDS AHEAD OF IT.
TRAJECTORY ANALYSIS SHOWS LLEVEL SOURCE REGION FOR AIR OVER NORTHERN
LOWER TODAY COMES FROM THE IOWA/ILLINOIS REGION 24 HOURS AGO...AN
AREA FEATURING A DEARTH OF LLEVEL MOISTURE. SO...BOUNDARY WILL BE
FIGHTING INCREASINGLY DRY ATMOSPHERE AS IT PUSHES SOUTH AND EAST
WITH LLEVEL MOISTURE TONGUE THINNING. LLEVEL CONVERGENCE IS
MODEST...BUT WILL HAVE SOME HELP FROM AN ARRIVING JET MAX /AND ITS
ASSOCIATED RIGHT ENTRANCE REGION/ AS WELL AS CONTINUED ISENTROPIC
ASCENT. NET RESULT: EXPECT A BROKEN LINE OF SHOWERS TO SINK SOUTH
DURING THE DAY...WEAKENING AS THEY DO SO. RECENT MODEL TRENDS HAVE
CONTINUED TO SLOW THE SOUTHWARD MOVEMENT OF ANY PRECIPITATION...
AND WHILE THIS FORECAST REPRESENTS A SLOWING TREND...IT COULD
REQUIRE FURTHER SLOWING WITH PRECIITATION POTENTIALLY COMPLETELY
FALLING APART BEFORE MAKING IT MUCH SOUTH OF M-32.
PTYPE: STARTS THE DAY ALL SNOW...BUT RAPIDLY WARMING SURFACE LAYER
SUGGESTS PREDOMINATE TYPE TO SWITCH TO RAIN COASTAL LOCALES BY LATE
MORNING AND ALL AREAS BY AFTERNOON. ONLY CAVEAT TO THIS WILL BE
OVER THE INTERIOR HIGH SPOTS WHERE WET BULBS IN THE MID 30S INDICATE
A FEW SNOWFLAKES MIGHT MIX IN AT ANY TIME...ESP IF PRECIPITATION
RATES ARE DECENT. OVERALL VERY LITTLE IMPACT EXPECTED...HOWEVER...
OUTSIDE OF A FEW SLICK SPOTS TO START THE DAY FROM THE BRIDGE
NORTH. PAVEMENT TEMPS WILL BE TOO WARM TO SUPPORT ANY ICING BY MID
MORNING OVER NORTHERN LOWER.
WINDS: PRETTY MUCH FULLY FORCED BY THE STRENGTH OF THE LOW LEVEL
JET /40-50KTS AT H9 EARLY...WEAKENING AS IT HEADS SOUTH/ AND THE
AMOUNT OF MIXING WE CAN DEVELOP AHEAD OF THE BOUNDARY. GIVEN A
SOMEWHAT SLOWER ARRIVAL TO THE BOUNDARY...MIXING HEIGHTS SHOULD GET
A CHANCE TO BUILD EARLY...WITH MOMENTUM TRANSPORT SUGGESTING WE CAN
LIKELY TAP 30KTS. SO...EXPECT SOUTHWEST WINDS 15-25 MPH WITH GUSTS
OVER 30 MPH BY LATE MORNING AND THROUGH THE AFTERNOON OVER
NORTHERN LOWER...A LITTLE WEAKER THAN THIS FURTHER NORTH.
TEMPS: T9 ROCKETS TO JUST ABOVE FREEZING AHEAD OF THE BOUNDARY...
WITH THE POTENTIAL TO PRODUCE LOW-MID 50S AHEAD OF THE BOUNDARY.
COMPLICATING THIS WILL BE CLOUDS AND PRECIP...WHICH...WITH PRETTY
SUBSTANTIAL LLEVEL DEWPOINT DEPRESSIONS SUGGESTS AMPLE OPPORTUNITY
FOR EVAPORATIONAL COOLING. WILL ALLOW SOUTHEASTERN ZONES TO MAKE A
RUN AT 55...WITH LOCALES NORTH OF THIS GENERALLY IN THE MID-UPPER
40S.
TONIGHT: NORTHWEST WINDS WILL USHER COLDER AIR INTO THE REGION AS
HIGH PRESSURE BUILDS IN FROM THE NORTHERN PLAINS. T8 FALLS TO -12C
SOUTH/-15C NORTH AFTER MIDNIGHT...WHICH WITH A MINOR AMOUNT OF
RESIDUAL 850-700MB MOISTURE SUGGESTS THAT SOME LAKE RESPONSE MAY TRY
AND GET GOING...BUT NOT UNTIL THE VERY END OF THIS PERIOD. WILL
CARRY CHANCE POPS AFTER 09Z BUT NO SIGNIFICANT SNOWFALL EXPECTED.
TEMPERATURES LOOK TO FALL INTO THE MID 20S AS COLD AIR ADVECTION IS
OFFSET SOMEWHAT BY RESIDUAL WINDS AND SOME LAKE CLOUDINESS /NORTH/.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM EDT THU APR 4 2013
FRIDAY...INITIALLY, THERE WILL BE SOME LIGHT SNOW AND FLURRIES IN E
UPPER, MAINLY NEAR WHITEFISH POINT AS THE 850 MB TEMPERATURES FALL
TO AROUND -14C WITH ABOUT 50% RH IN THE 850-700 MB LAYER. THIS WILL
BE MAINLY IN THE MORNING, BECAUSE AS THE HIGH PRESSURE BUILDS INTO
THE REGION MORE DRY AIR PUSHES INTO THE FORECAST AREA, AND THE 850
MB TEMPERATURES RISE ABOVE -12C BY 18Z. SO WILL GO WITH A DRY DAY
OVERALL.
FRIDAY NIGHT...THE WARM ADVECTION WING FROM THE NEXT SYSTEM BEGINS
TO MOVE INTO THE REGION, ESPECIALLY AFTER 06Z. THIS WILL BRING A
CHANCE OF SNOW BY 12Z IN THE WESTERN PART OF THE FORECAST AREA. THE
LOWER LEVEL MOISTURE WILL BE THE MAIN CONCERN AS THE POPS ARE DRAWN
ROUGHLY WHERE THE 850 MB MOISTURE IS ABOVE 50%. HOWEVER, THIS COULD
JUST AS EASILY BE NOTHING UNTIL THE DAY ON SATURDAY, IF THE ATMOSPHERE
DOESN`T SATURATE FAST ENOUGH.
SATURDAY...THE WARM FRONT MOVES NORTH A BIT, BUT FOR THE MOISTURE
PART ONCE IT GETS TO AROUND THE STRAITS, IT LOOKS LIKE IT TRAVELS
EAST, WITH THE SFC LOW FOLLOWING ALONG IT. THIS SETS UP SNOW IN E
UPPER, WHICH COULD HAVE LIGHT TO MODERATE AMOUNTS THROUGH THE DAY.
WOULD EXPECT A MIX, ESPECIALLY BETWEEN M-32 AND THE STRAITS AS THE
PROFILES ARE EITHER ON THE 0C LINE. SOUTH OF M-32, THINK THAT IT
WILL BE MAINLY RAIN. OVERNIGHT, THE WARMER AIR WITH BOTH MODELS,
GETS TO THE STRAITS, THE RAIN WILL LIKELY GET ALL THE WAY TO THE
STRAITS, AND WE`LL GET A MIX IN E UPPER. THE CONCERN, BASED ON THE
PROFILES OF BOTH MODELS, IS THAT WE WILL PARTIALLY MELT SOME OF
THE SNOW (TEMPERATURES IN THE PROFILE GET TO +2C AROUND 850 MB
THEN FALL TO OR BELOW 0C IN E UPPER). SO WILL GO WITH SNOW/RAIN OR
FREEZING RAIN MIX AT THIS POINT, AND KEEP IT MENTIONED IN HWOAPX.
THE COLD AIR MOVES INTO E UPPER AGAIN ONCE THE LOW MOVES EAST. SO
E UPPER WILL SEE A CHANGE OVER AGAIN BETWEEN 06Z AND 12Z.
EXTENDED (SUNDAY THROUGH WEDNESDAY)...SUNDAY, THE MODELS MOVE THE
LOW EAST OF THE REGION AND THE COLD AIR MOVES BACK. HOWEVER, THINGS
ARE DRY ENOUGH AND WARM ENOUGH, THAT LITTLE IF NO PRECIPITATION WILL
FALL. MONDAY, LOOKS LIKE ANOTHER WAVE FORMS ON THE FRONT THAT
STALLS IT, AND EVEN ALLOWS FOR SOME WARMING. SO WILL GO WITH
CHANCE OF RAIN IN N LOWER AND A MIX IN E UPPER. TUESDAY, THE LOW
NO LONGER MOVES OUT OF THE MID MISSISSIPPI VALLEY AS THE MODELS
FOCUS DEVELOPMENT ON THE CLOSED 500 MB LOW IN THE SOUTHWEST
STATES. THIS WOULD KEEP THE SFC LOW IN TX/OK REGION WITH A WARM
FRONT/SFC TROUGH THAT IS STALLED IN THE OHIO VALLEY. OVERNIGHT,
THE GFS BEGINS TO LIFT THE 500 MB LOW INTO THE NORTHERN BRANCH.
THE ECMWF LOOKS BETTER WITH THE SLOWER LIFTING OF THE WAVE KEEPING
THE RAIN AND THE WARM FRONT ALONG OR SOUTH OF THE OHIO VALLEY.
WEDNESDAY, THINKING THAT THE GFS IS TOO WET, DUE TO THE PHASING OF
THE SYSTEMS. WOULD BE MORE INCLINED TO GO WITH THE ECMWF IDEA WITH
THE HIGH SETTLING IN OVER THE GREAT LAKES. WHICH WOULD KEEP US
DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 156 PM EDT THU APR 4 2013
VFR CIGS AND VSBY IN ADVANCE OF A FRONTAL BOUNDARY DROPPING SOUTH ACRS
NRN LWR MI...WILL TREND MVFR AND OCCASIONALLY IFR IN MIXED RAIN
AND SNOW THROUGH BTWN 00Z AND 03Z. COLDER AIR AND NORTHWEST WINDS
ON THE BACK SIDE OF THE EXITING SYSTEM...WILL GENERATE SOME LAKE
SNOWS OVER TAF SITE KTVC AND KMBL FRIDAY. GUSTY SOUTHWEST WINDS IN
ADVANCE OF THE BOUNDARY...WILL TREND NORTHWEST ACRS NRN LWR MI TAF
SITES BTWN 00Z AND 06Z.
&&
.MARINE...
ISSUED AT 420 AM EDT THU APR 4 2013
SUMMARY: A COLD FRONT WILL PUSH THROUGH NORTHERN MICHIGAN TODAY WITH
GUSTY SOUTHWEST WINDS AHEAD OF IT SHIFTING NORTHWESTERLY BEHIND IT
THIS EVENING AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION.
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH FRIDAY
NIGHT.
HEADLINES: GALE WARNING THROUGH LATE MORNING STILL LOOKS GOOD OVER
PORTIONS OF NORTHERN LAKE MICHIGAN. ELSEWHERE...WILL EXPAND SMALL
CRAFTS TO ALL ZONES FOR TODAY GIVEN ROBUST WIND FIELD AHEAD OF
APPROACHING COLD FRONT. MARGINAL SMALL CRAFT CONDITIONS CONTINUE
THROUGH TONIGHT BEFORE A BREAK IN WIND/WAVE ACTIVITY IS EXPECTED
FRIDAY. NEXT STORM SYSTEM ARRIVES SATURDAY WITH A RENEWED PERIOD OF
SMALL CRAFTS LIKELY THROUGHOUT THE NEARSHORE WATERS OF NORTHERN
MICHIGAN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-345-
346.
GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ341-342-344.
LS...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ321-322.
&&
$$
UPDATE...SR
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...SR
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
935 AM EDT THU APR 4 2013
.SYNOPSIS...
ISSUED AT 420 AM EDT THU APR 4 2013
A COLD FRONT WILL MOVE THROUGH NORTHERN MICHIGAN TODAY.
PRECIPITATION ASSOCIATED WITH THIS FRONT WILL START AS SNOW THIS
MORNING...BUT MIX WITH RAIN AS THE TEMPERATURES RISE ABOVE
FREEZING TODAY. THE RAIN WILL END IN THE AFTERNOON AS DRIER TAKES
OVER BEFORE THE FRONT MOVES THROUGH. HIGH PRESSURE AND COOLER
TEMPERATURES WILL SETTLE IN FOR THURSDAY NIGHT AND FRIDAY BEFORE A
STORM SYSTEM MOVES INTO NORTHERN MICHIGAN AND HANGS AROUND FOR
MUCH OF THE WEEKEND...BRINGING RAIN AND SNOW MIXED FOR SATURDAY
AND SUNDAY.
&&
.UPDATE...
ISSUED AT 933 AM EDT THU APR 4 2013
CURRENT RADAR AND SFC OBS SHOWING AREA OF PCPN OVER ERN UPPER AND
STRAITS REGION...WHICH IS IN RESPONSE TO A COLD FRONT PUSHING INTO
THE WRN LAKES. PCPN ASSOCIATED WITH THIS FRONT SO FAR THIS MORNING
HAS BEEN CONFINED TO A NARROW BAND...HINDERED GREATLY BY LIMITED
MSTR. SFC DEW PTS SOUTH OF THE STRAITS ARE CURRENTLY IN THE
TEENS...THOUGH DEW PTS HAVE INCREASED INTO THE LOWER AND MID 20 OVER
ERN UPPER JUST IN ADVANCE OF THE FRONT.
AS FOR THE REST OF TODAY...LIMITED MSTR WILL REMAIN A HINDRANCE
THROUGH THE AFTERNOON OVR NRN LWR MI...KEEPING ANY PCPN CONFINED TO
A NARROW AREA RIGHT ALONG THE FRONT. MODEL SOUNDINGS SHOW PCPN CHCS
ENDING FROM GLR NORTH BTWN 18Z AND 21Z...AND ENDING NEAR SAGINAW BAY
REGION BETWEEN 00Z AND 03Z.
OVERALL CURRENT FCST IN LINE WITH MILD TEMP AND SUN EARLY OVER THE
SRN CWA...WITH PCPN ENDING OVER ERN UPPER EARLY THIS AFTN.
UPDATE ISSUED AT 607 AM EDT THU APR 4 2013
CHANGES THIS HOUR: HAVE CONTINUED SLOWING TREND OF POPS THROUGH
MUCH OF TODAY GIVEN RECENT GOOD AGREEMENT BETWEEN THE NAM/RAP/HRRR
GIVEN VERY IMPRESSIVE PERFORMANCE FROM THE RAP OVER THE PAST FEW
HOURS. SNOWFALL HAS ARRIVED FROM SAW-ERY-ANJ AND WILL GO AHEAD AND
BUMP UP NEAR TERM POPS TO CATEGORICAL FOR NORTHERN CHIPPEWA
THROUGH DAYBREAK. BEYOND THIS...INITIAL SURGE OF ISENTROPIC ASCENT
ALONG LLEVEL MOISTURE AXIS WILL SHIFT EAST AND WE/LL THEN AWAIT
FURTHER DEVELOPMENT ALONG THE FRONTAL BOUNDARY ITSELF...WHICH IS
NOW SLIDING SOUTHEAST THROUGH WESTERN UPPER. DON/T EXPECT THIS TO
BE SUBSTANTIAL...AND AS PREVIOUSLY MENTIONED...EXPECT IT TO
DWINDLE AS IT HEADS SOUTH...WITH RAIN GRADUALLY TAKING OVER AS THE
PREDOMINATE PRECIPITATION TYPE.
COULD SEE AN INCH OF MORNING ACCUMS FROM PARADISE TO ANJ /WEBCAMS
SHOW A COATING ATTM/...SO WATCH OUT FOR SOME SLICK AM TRAVEL IN
THESE SPOTS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 420 AM EDT THU APR 4 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WINDS OVER MUCH OF
NORTHERN LAKE MICHIGAN THROUGH MID MORNING. WILL LIKELY HAVE SOME
COASTAL WIND GUSTS ABOVE 30 MPH TODAY...OTHERWISE...NO HIGH
IMPACT WEATHER EXPECTED.
OVERVIEW: SURFACE MAP EARLY THIS MORNING REVEALS HIGH PRESSURE
RESPONSIBLE FOR THE BEAUTIFUL /ALBEIT CHILLY/ AFTERNOON YESTERDAY
HAVING PUSHED SOUTH AND EAST INTO THE OHIO VALLEY/MID ATLANTIC
REGION...THIS HAS ALLOWED BROAD SOUTHWESTERLY FLOW TO DEVELOP BETWEEN
THIS FEATURE AND RATHER IMPRESSIVE SURFACE LOW NOW TRAVELING FROM
WEST TO EAST ACROSS NORTHERN ONTARIO. PRIMARY FEATURE OF NOTE
THROUGH THE SHORT TERM PORTION OF THE FORECAST IS A COLD FRONT
DRAPED TO THE SOUTH AND WEST OF THIS LOW...APPROACHING LAKE SUPERIOR
AS OF THIS WRITING. STRENGTHENING SOUTHWESTERLY WINDS OVER NORTHERN
MICHIGAN HAVE PRECLUDED STEEP TEMPERATURE FALLS OVERNIGHT WITH MOST
LOCATIONS AT LEAST 10F WARMER THAN 24 HOURS AGO. LLEVEL MOISTURE
HAS NOT RESPONDED IN TANDEM...WITH 00Z APX RAOB SHOWING A PALTRY
0.14" PWAT. CLOSER TO THE FRONT...HOWEVER...PRECIPITATION ECHOES
HAVE BEEN BLOSSOMING OVER THE PAST COUPLE OF HOURS AS ROBUST LOW
LEVEL JET AT H8 /50KTS+/ TRANSPORTS A PLUME OF 2/3" PWATS RAPIDLY
EASTWARD.
THROUGH DAYBREAK: WINDS CONTINUE TO RAMP UP FROM WEST TO EAST...WITH
SLOWLY INCREASING MID AND UPPER LEVEL CLOUDINESS...PRIMARILY FROM THE
STRAITS NORTH. TIMING AREA OF INCREASING RADAR ECHOES SUGGESTS
PRECIPITATION COULD ARRIVE AS EARLY AS 5-6AM OVER EASTERN UPPER AS
SOME SNOW SHOWERS. INTERESTING TO NOTE SURFACE DEWPOINT TREND OVER
THE PAST FEW HOURS OVER NORTHERN LOWER...WITH VALUES PLUMMETING TO
BELOW 10F AT TVC/CAD AND ROPPING EVERYWHERE AWAY FROM LAKE
MICHIGAN. THIS SUGGESTS THE SLOWING TREND IN FRONTAL PRECIP
ARRIVAL /SEEN IN RECENT RENDTIONS OF THE HRRR/RAP/ ARE LIKELY ON
THE RIGHT TRACK.
TODAY: COLD FRONT PUSHES THROUGH NORTHERN MICHIGAN TODAY...STARTING
THE DAY OVER WESTERN UPPER AND REACHING MY SOUTHEASTERN ZONES BY
EVENING. PRIMARY CONCERNS TODAY CENTER AROUND PRECIPITATION
CHANCES AS THIS BOUNDARY MOVES THROUGH...AS WELL AS THE STRENGTH
OF SOUTHWESTERLY WINDS AHEAD OF IT.
TRAJECTORY ANALYSIS SHOWS LLEVEL SOURCE REGION FOR AIR OVER NORTHERN
LOWER TODAY COMES FROM THE IOWA/ILLINOIS REGION 24 HOURS AGO...AN
AREA FEATURING A DEARTH OF LLEVEL MOISTURE. SO...BOUNDARY WILL BE
FIGHTING INCREASINGLY DRY ATMOSPHERE AS IT PUSHES SOUTH AND EAST
WITH LLEVEL MOISTURE TONGUE THINNING. LLEVEL CONVERGENCE IS
MODEST...BUT WILL HAVE SOME HELP FROM AN ARRIVING JET MAX /AND ITS
ASSOCIATED RIGHT ENTRANCE REGION/ AS WELL AS CONTINUED ISENTROPIC
ASCENT. NET RESULT: EXPECT A BROKEN LINE OF SHOWERS TO SINK SOUTH
DURING THE DAY...WEAKENING AS THEY DO SO. RECENT MODEL TRENDS HAVE
CONTINUED TO SLOW THE SOUTHWARD MOVEMENT OF ANY PRECIPITATION...
AND WHILE THIS FORECAST REPRESENTS A SLOWING TREND...IT COULD
REQUIRE FURTHER SLOWING WITH PRECIITATION POTENTIALLY COMPLETELY
FALLING APART BEFORE MAKING IT MUCH SOUTH OF M-32.
PTYPE: STARTS THE DAY ALL SNOW...BUT RAPIDLY WARMING SURFACE LAYER
SUGGESTS PREDOMINATE TYPE TO SWITCH TO RAIN COASTAL LOCALES BY LATE
MORNING AND ALL AREAS BY AFTERNOON. ONLY CAVEAT TO THIS WILL BE
OVER THE INTERIOR HIGH SPOTS WHERE WET BULBS IN THE MID 30S INDICATE
A FEW SNOWFLAKES MIGHT MIX IN AT ANY TIME...ESP IF PRECIPITATION
RATES ARE DECENT. OVERALL VERY LITTLE IMPACT EXPECTED...HOWEVER...
OUTSIDE OF A FEW SLICK SPOTS TO START THE DAY FROM THE BRIDGE
NORTH. PAVEMENT TEMPS WILL BE TOO WARM TO SUPPORT ANY ICING BY MID
MORNING OVER NORTHERN LOWER.
WINDS: PRETTY MUCH FULLY FORCED BY THE STRENGTH OF THE LOW LEVEL
JET /40-50KTS AT H9 EARLY...WEAKENING AS IT HEADS SOUTH/ AND THE
AMOUNT OF MIXING WE CAN DEVELOP AHEAD OF THE BOUNDARY. GIVEN A
SOMEWHAT SLOWER ARRIVAL TO THE BOUNDARY...MIXING HEIGHTS SHOULD GET
A CHANCE TO BUILD EARLY...WITH MOMENTUM TRANSPORT SUGGESTING WE CAN
LIKELY TAP 30KTS. SO...EXPECT SOUTHWEST WINDS 15-25 MPH WITH GUSTS
OVER 30 MPH BY LATE MORNING AND THROUGH THE AFTERNOON OVER
NORTHERN LOWER...A LITTLE WEAKER THAN THIS FURTHER NORTH.
TEMPS: T9 ROCKETS TO JUST ABOVE FREEZING AHEAD OF THE BOUNDARY...
WITH THE POTENTIAL TO PRODUCE LOW-MID 50S AHEAD OF THE BOUNDARY.
COMPLICATING THIS WILL BE CLOUDS AND PRECIP...WHICH...WITH PRETTY
SUBSTANTIAL LLEVEL DEWPOINT DEPRESSIONS SUGGESTS AMPLE OPPORTUNITY
FOR EVAPORATIONAL COOLING. WILL ALLOW SOUTHEASTERN ZONES TO MAKE A
RUN AT 55...WITH LOCALES NORTH OF THIS GENERALLY IN THE MID-UPPER
40S.
TONIGHT: NORTHWEST WINDS WILL USHER COLDER AIR INTO THE REGION AS
HIGH PRESSURE BUILDS IN FROM THE NORTHERN PLAINS. T8 FALLS TO -12C
SOUTH/-15C NORTH AFTER MIDNIGHT...WHICH WITH A MINOR AMOUNT OF
RESIDUAL 850-700MB MOISTURE SUGGESTS THAT SOME LAKE RESPONSE MAY TRY
AND GET GOING...BUT NOT UNTIL THE VERY END OF THIS PERIOD. WILL
CARRY CHANCE POPS AFTER 09Z BUT NO SIGNIFICANT SNOWFALL EXPECTED.
TEMPERATURES LOOK TO FALL INTO THE MID 20S AS COLD AIR ADVECTION IS
OFFSET SOMEWHAT BY RESIDUAL WINDS AND SOME LAKE CLOUDINESS /NORTH/.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM EDT THU APR 4 2013
FRIDAY...INITIALLY, THERE WILL BE SOME LIGHT SNOW AND FLURRIES IN E
UPPER, MAINLY NEAR WHITEFISH POINT AS THE 850 MB TEMPERATURES FALL
TO AROUND -14C WITH ABOUT 50% RH IN THE 850-700 MB LAYER. THIS WILL
BE MAINLY IN THE MORNING, BECAUSE AS THE HIGH PRESSURE BUILDS INTO
THE REGION MORE DRY AIR PUSHES INTO THE FORECAST AREA, AND THE 850
MB TEMPERATURES RISE ABOVE -12C BY 18Z. SO WILL GO WITH A DRY DAY
OVERALL.
FRIDAY NIGHT...THE WARM ADVECTION WING FROM THE NEXT SYSTEM BEGINS
TO MOVE INTO THE REGION, ESPECIALLY AFTER 06Z. THIS WILL BRING A
CHANCE OF SNOW BY 12Z IN THE WESTERN PART OF THE FORECAST AREA. THE
LOWER LEVEL MOISTURE WILL BE THE MAIN CONCERN AS THE POPS ARE DRAWN
ROUGHLY WHERE THE 850 MB MOISTURE IS ABOVE 50%. HOWEVER, THIS COULD
JUST AS EASILY BE NOTHING UNTIL THE DAY ON SATURDAY, IF THE ATMOSPHERE
DOESN`T SATURATE FAST ENOUGH.
SATURDAY...THE WARM FRONT MOVES NORTH A BIT, BUT FOR THE MOISTURE
PART ONCE IT GETS TO AROUND THE STRAITS, IT LOOKS LIKE IT TRAVELS
EAST, WITH THE SFC LOW FOLLOWING ALONG IT. THIS SETS UP SNOW IN E
UPPER, WHICH COULD HAVE LIGHT TO MODERATE AMOUNTS THROUGH THE DAY.
WOULD EXPECT A MIX, ESPECIALLY BETWEEN M-32 AND THE STRAITS AS THE
PROFILES ARE EITHER ON THE 0C LINE. SOUTH OF M-32, THINK THAT IT
WILL BE MAINLY RAIN. OVERNIGHT, THE WARMER AIR WITH BOTH MODELS,
GETS TO THE STRAITS, THE RAIN WILL LIKELY GET ALL THE WAY TO THE
STRAITS, AND WE`LL GET A MIX IN E UPPER. THE CONCERN, BASED ON THE
PROFILES OF BOTH MODELS, IS THAT WE WILL PARTIALLY MELT SOME OF
THE SNOW (TEMPERATURES IN THE PROFILE GET TO +2C AROUND 850 MB
THEN FALL TO OR BELOW 0C IN E UPPER). SO WILL GO WITH SNOW/RAIN OR
FREEZING RAIN MIX AT THIS POINT, AND KEEP IT MENTIONED IN HWOAPX.
THE COLD AIR MOVES INTO E UPPER AGAIN ONCE THE LOW MOVES EAST. SO
E UPPER WILL SEE A CHANGE OVER AGAIN BETWEEN 06Z AND 12Z.
EXTENDED (SUNDAY THROUGH WEDNESDAY)...SUNDAY, THE MODELS MOVE THE
LOW EAST OF THE REGION AND THE COLD AIR MOVES BACK. HOWEVER, THINGS
ARE DRY ENOUGH AND WARM ENOUGH, THAT LITTLE IF NO PRECIPITATION WILL
FALL. MONDAY, LOOKS LIKE ANOTHER WAVE FORMS ON THE FRONT THAT
STALLS IT, AND EVEN ALLOWS FOR SOME WARMING. SO WILL GO WITH
CHANCE OF RAIN IN N LOWER AND A MIX IN E UPPER. TUESDAY, THE LOW
NO LONGER MOVES OUT OF THE MID MISSISSIPPI VALLEY AS THE MODELS
FOCUS DEVELOPMENT ON THE CLOSED 500 MB LOW IN THE SOUTHWEST
STATES. THIS WOULD KEEP THE SFC LOW IN TX/OK REGION WITH A WARM
FRONT/SFC TROUGH THAT IS STALLED IN THE OHIO VALLEY. OVERNIGHT,
THE GFS BEGINS TO LIFT THE 500 MB LOW INTO THE NORTHERN BRANCH.
THE ECMWF LOOKS BETTER WITH THE SLOWER LIFTING OF THE WAVE KEEPING
THE RAIN AND THE WARM FRONT ALONG OR SOUTH OF THE OHIO VALLEY.
WEDNESDAY, THINKING THAT THE GFS IS TOO WET, DUE TO THE PHASING OF
THE SYSTEMS. WOULD BE MORE INCLINED TO GO WITH THE ECMWF IDEA WITH
THE HIGH SETTLING IN OVER THE GREAT LAKES. WHICH WOULD KEEP US
DRY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 640 AM EDT THU APR 4 2013
SUMMARY: A MOISTURE-STARVED COLD FRONT WILL DROP THROUGH THE STATE
TODAY...BRINGING A LINE OF RAIN AND SNOW SHOWERS. HIGH PRESSURE
WILL BUILD IN BEHIND THIS FRONT TONIGHT...WITH SOME LAKE INDUCED
CLOUDINESS DEVELOPING.
RESTRICTIONS: EXPECT APN/TVC/MBL TO REMAIN VFR THROUGH THE UPCOMING
TAF PERIOD...WITH A BRIEF PERIOD OF MVFR STILL EXPECTED THIS
AFTERNOON /ALBEIT SOMEWHAT LATER THAN PREVIOUSLY EXPECTED/ AT PLN.
EXPECT SHRASN TO IMPACT THIS SITE WITH MVFR CIGS DEVELOPING AFTER
21Z IMMEDIATELY BEHIND THE DEPARTING COLD FRONT. THESE CLOUDS WILL
LIFT DURING THE EVENING WITH VFR CLOUDINESS /4KFT/ OVERNIGHT.
WINDS: SOUTHWEST WINDS WILL STRENGTHEN TO 15G25KTS FOR THE BY MID
MORNING AND CONTINUE THROUGH THE AFTERNOON WHILE GRADUALLY VEERING
WEST. LATE THIS AFTERNOON WILL SHIFT NORTHWESTERLY AND DIMINISH TO
AROUND 10KTS THIS EVENING AND OVERNIGHT.
LLWS: SOUTHWEST WINDS AT 1.5-2KFT STILL REACHING AROUND 40 KTS AND
GIVEN THAT THE TERMINALS REMAIN SOMEWHAT DECOUPLED FROM THIS
STRONGER FLOW ALOFT...WILL LEAVE LLWS MENTION IN THROUGH 14Z BEFORE
DAYTIME MIXING ELIMINATES ANY POTENTIAL SHEAR LAYERS.
&&
.MARINE...
ISSUED AT 420 AM EDT THU APR 4 2013
SUMMARY: A COLD FRONT WILL PUSH THROUGH NORTHERN MICHIGAN TODAY WITH
GUSTY SOUTHWEST WINDS AHEAD OF IT SHIFTING NORTHWESTERLY BEHIND IT
THIS EVENING AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION.
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH FRIDAY
NIGHT.
HEADLINES: GALE WARNING THROUGH LATE MORNING STILL LOOKS GOOD OVER
PORTIONS OF NORTHERN LAKE MICHIGAN. ELSEWHERE...WILL EXPAND SMALL
CRAFTS TO ALL ZONES FOR TODAY GIVEN ROBUST WIND FIELD AHEAD OF
APPROACHING COLD FRONT. MARGINAL SMALL CRAFT CONDITIONS CONTINUE
THROUGH TONIGHT BEFORE A BREAK IN WIND/WAVE ACTIVITY IS EXPECTED
FRIDAY. NEXT STORM SYSTEM ARRIVES SATURDAY WITH A RENEWED PERIOD OF
SMALL CRAFTS LIKELY THROUGHOUT THE NEARSHORE WATERS OF NORTHERN
MICHIGAN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
345-346.
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LMZ341-342-344.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ321-
322.
&&
$$
UPDATE...SR
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
642 AM EDT THU APR 4 2013
.SYNOPSIS...
ISSUED AT 420 AM EDT THU APR 4 2013
A COLD FRONT WILL MOVE THROUGH NORTHERN MICHIGAN TODAY.
PRECIPITATION ASSOCIATED WITH THIS FRONT WILL START AS SNOW THIS
MORNING...BUT MIX WITH RAIN AS THE TEMPERATURES RISE ABOVE
FREEZING TODAY. THE RAIN WILL END IN THE AFTERNOON AS DRIER TAKES
OVER BEFORE THE FRONT MOVES THROUGH. HIGH PRESSURE AND COOLER
TEMPERATURES WILL SETTLE IN FOR THURSDAY NIGHT AND FRIDAY BEFORE A
STORM SYSTEM MOVES INTO NORTHERN MICHIGAN AND HANGS AROUND FOR
MUCH OF THE WEEKEND...BRINGING RAIN AND SNOW MIXED FOR SATURDAY
AND SUNDAY.
&&
.UPDATE...
ISSUED AT 607 AM EDT THU APR 4 2013
CHANGES THIS HOUR: HAVE CONTINUED SLOWING TREND OF POPS THROUGH
MUCH OF TODAY GIVEN RECENT GOOD AGREEMENT BETWEEN THE NAM/RAP/HRRR
GIVEN VERY IMPRESSIVE PERFORMANCE FROM THE RAP OVER THE PAST FEW
HOURS. SNOWFALL HAS ARRIVED FROM SAW-ERY-ANJ AND WILL GO AHEAD AND
BUMP UP NEAR TERM POPS TO CATEGORICAL FOR NORTHERN CHIPPEWA
THROUGH DAYBREAK. BEYOND THIS...INITIAL SURGE OF ISENTROPIC ASCENT
ALONG LLEVEL MOISTURE AXIS WILL SHIFT EAST AND WE/LL THEN AWAIT
FURTHER DEVELOPMENT ALONG THE FRONTAL BOUNDARY ITSELF...WHICH IS
NOW SLIDING SOUTHEAST THROUGH WESTERN UPPER. DON/T EXPECT THIS TO
BE SUBSTANTIAL...AND AS PREVIOUSLY MENTIONED...EXPECT IT TO
DWINDLE AS IT HEADS SOUTH...WITH RAIN GRADUALLY TAKING OVER AS THE
PREDOMINATE PRECIPITATION TYPE.
COULD SEE AN INCH OF MORNING ACCUMS FROM PARADISE TO ANJ /WEBCAMS
SHOW A COATING ATTM/...SO WATCH OUT FOR SOME SLICK AM TRAVEL IN
THESE SPOTS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 420 AM EDT THU APR 4 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WINDS OVER MUCH OF
NORTHERN LAKE MICHIGAN THROUGH MID MORNING. WILL LIKELY HAVE SOME
COASTAL WIND GUSTS ABOVE 30 MPH TODAY...OTHERWISE...NO HIGH
IMPACT WEATHER EXPECTED.
OVERVIEW: SURFACE MAP EARLY THIS MORNING REVEALS HIGH PRESSURE
RESPONSIBLE FOR THE BEAUTIFUL /ALBEIT CHILLY/ AFTERNOON YESTERDAY
HAVING PUSHED SOUTH AND EAST INTO THE OHIO VALLEY/MID ATLANTIC
REGION...THIS HAS ALLOWED BROAD SOUTHWESTERLY FLOW TO DEVELOP BETWEEN
THIS FEATURE AND RATHER IMPRESSIVE SURFACE LOW NOW TRAVELING FROM
WEST TO EAST ACROSS NORTHERN ONTARIO. PRIMARY FEATURE OF NOTE
THROUGH THE SHORT TERM PORTION OF THE FORECAST IS A COLD FRONT
DRAPED TO THE SOUTH AND WEST OF THIS LOW...APPROACHING LAKE SUPERIOR
AS OF THIS WRITING. STRENGTHENING SOUTHWESTERLY WINDS OVER NORTHERN
MICHIGAN HAVE PRECLUDED STEEP TEMPERATURE FALLS OVERNIGHT WITH MOST
LOCATIONS AT LEAST 10F WARMER THAN 24 HOURS AGO. LLEVEL MOISTURE
HAS NOT RESPONDED IN TANDEM...WITH 00Z APX RAOB SHOWING A PALTRY
0.14" PWAT. CLOSER TO THE FRONT...HOWEVER...PRECIPITATION ECHOES
HAVE BEEN BLOSSOMING OVER THE PAST COUPLE OF HOURS AS ROBUST LOW
LEVEL JET AT H8 /50KTS+/ TRANSPORTS A PLUME OF 2/3" PWATS RAPIDLY
EASTWARD.
THROUGH DAYBREAK: WINDS CONTINUE TO RAMP UP FROM WEST TO EAST...WITH
SLOWLY INCREASING MID AND UPPER LEVEL CLOUDINESS...PRIMARILY FROM THE
STRAITS NORTH. TIMING AREA OF INCREASING RADAR ECHOES SUGGESTS
PRECIPITATION COULD ARRIVE AS EARLY AS 5-6AM OVER EASTERN UPPER AS
SOME SNOW SHOWERS. INTERESTING TO NOTE SURFACE DEWPOINT TREND OVER
THE PAST FEW HOURS OVER NORTHERN LOWER...WITH VALUES PLUMMETING TO
BELOW 10F AT TVC/CAD AND ROPPING EVERYWHERE AWAY FROM LAKE
MICHIGAN. THIS SUGGESTS THE SLOWING TREND IN FRONTAL PRECIP
ARRIVAL /SEEN IN RECENT RENDTIONS OF THE HRRR/RAP/ ARE LIKELY ON
THE RIGHT TRACK.
TODAY: COLD FRONT PUSHES THROUGH NORTHERN MICHIGAN TODAY...STARTING
THE DAY OVER WESTERN UPPER AND REACHING MY SOUTHEASTERN ZONES BY
EVENING. PRIMARY CONCERNS TODAY CENTER AROUND PRECIPITATION
CHANCES AS THIS BOUNDARY MOVES THROUGH...AS WELL AS THE STRENGTH
OF SOUTHWESTERLY WINDS AHEAD OF IT.
TRAJECTORY ANALYSIS SHOWS LLEVEL SOURCE REGION FOR AIR OVER NORTHERN
LOWER TODAY COMES FROM THE IOWA/ILLINOIS REGION 24 HOURS AGO...AN
AREA FEATURING A DEARTH OF LLEVEL MOISTURE. SO...BOUNDARY WILL BE
FIGHTING INCREASINGLY DRY ATMOSPHERE AS IT PUSHES SOUTH AND EAST
WITH LLEVEL MOISTURE TONGUE THINNING. LLEVEL CONVERGENCE IS
MODEST...BUT WILL HAVE SOME HELP FROM AN ARRIVING JET MAX /AND ITS
ASSOCIATED RIGHT ENTRANCE REGION/ AS WELL AS CONTINUED ISENTROPIC
ASCENT. NET RESULT: EXPECT A BROKEN LINE OF SHOWERS TO SINK SOUTH
DURING THE DAY...WEAKENING AS THEY DO SO. RECENT MODEL TRENDS HAVE
CONTINUED TO SLOW THE SOUTHWARD MOVEMENT OF ANY PRECIPITATION...
AND WHILE THIS FORECAST REPRESENTS A SLOWING TREND...IT COULD
REQUIRE FURTHER SLOWING WITH PRECIITATION POTENTIALLY COMPLETELY
FALLING APART BEFORE MAKING IT MUCH SOUTH OF M-32.
PTYPE: STARTS THE DAY ALL SNOW...BUT RAPIDLY WARMING SURFACE LAYER
SUGGESTS PREDOMINATE TYPE TO SWITCH TO RAIN COASTAL LOCALES BY LATE
MORNING AND ALL AREAS BY AFTERNOON. ONLY CAVEAT TO THIS WILL BE
OVER THE INTERIOR HIGH SPOTS WHERE WET BULBS IN THE MID 30S INDICATE
A FEW SNOWFLAKES MIGHT MIX IN AT ANY TIME...ESP IF PRECIPITATION
RATES ARE DECENT. OVERALL VERY LITTLE IMPACT EXPECTED...HOWEVER...
OUTSIDE OF A FEW SLICK SPOTS TO START THE DAY FROM THE BRIDGE
NORTH. PAVEMENT TEMPS WILL BE TOO WARM TO SUPPORT ANY ICING BY MID
MORNING OVER NORTHERN LOWER.
WINDS: PRETTY MUCH FULLY FORCED BY THE STRENGTH OF THE LOW LEVEL
JET /40-50KTS AT H9 EARLY...WEAKENING AS IT HEADS SOUTH/ AND THE
AMOUNT OF MIXING WE CAN DEVELOP AHEAD OF THE BOUNDARY. GIVEN A
SOMEWHAT SLOWER ARRIVAL TO THE BOUNDARY...MIXING HEIGHTS SHOULD GET
A CHANCE TO BUILD EARLY...WITH MOMENTUM TRANSPORT SUGGESTING WE CAN
LIKELY TAP 30KTS. SO...EXPECT SOUTHWEST WINDS 15-25 MPH WITH GUSTS
OVER 30 MPH BY LATE MORNING AND THROUGH THE AFTERNOON OVER
NORTHERN LOWER...A LITTLE WEAKER THAN THIS FURTHER NORTH.
TEMPS: T9 ROCKETS TO JUST ABOVE FREEZING AHEAD OF THE BOUNDARY...
WITH THE POTENTIAL TO PRODUCE LOW-MID 50S AHEAD OF THE BOUNDARY.
COMPLICATING THIS WILL BE CLOUDS AND PRECIP...WHICH...WITH PRETTY
SUBSTANTIAL LLEVEL DEWPOINT DEPRESSIONS SUGGESTS AMPLE OPPORTUNITY
FOR EVAPORATIONAL COOLING. WILL ALLOW SOUTHEASTERN ZONES TO MAKE A
RUN AT 55...WITH LOCALES NORTH OF THIS GENERALLY IN THE MID-UPPER
40S.
TONIGHT: NORTHWEST WINDS WILL USHER COLDER AIR INTO THE REGION AS
HIGH PRESSURE BUILDS IN FROM THE NORTHERN PLAINS. T8 FALLS TO -12C
SOUTH/-15C NORTH AFTER MIDNIGHT...WHICH WITH A MINOR AMOUNT OF
RESIDUAL 850-700MB MOISTURE SUGGESTS THAT SOME LAKE RESPONSE MAY TRY
AND GET GOING...BUT NOT UNTIL THE VERY END OF THIS PERIOD. WILL
CARRY CHANCE POPS AFTER 09Z BUT NO SIGNIFICANT SNOWFALL EXPECTED.
TEMPERATURES LOOK TO FALL INTO THE MID 20S AS COLD AIR ADVECTION IS
OFFSET SOMEWHAT BY RESIDUAL WINDS AND SOME LAKE CLOUDINESS /NORTH/.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM EDT THU APR 4 2013
FRIDAY...INITIALLY, THERE WILL BE SOME LIGHT SNOW AND FLURRIES IN E
UPPER, MAINLY NEAR WHITEFISH POINT AS THE 850 MB TEMPERATURES FALL
TO AROUND -14C WITH ABOUT 50% RH IN THE 850-700 MB LAYER. THIS WILL
BE MAINLY IN THE MORNING, BECAUSE AS THE HIGH PRESSURE BUILDS INTO
THE REGION MORE DRY AIR PUSHES INTO THE FORECAST AREA, AND THE 850
MB TEMPERATURES RISE ABOVE -12C BY 18Z. SO WILL GO WITH A DRY DAY
OVERALL.
FRIDAY NIGHT...THE WARM ADVECTION WING FROM THE NEXT SYSTEM BEGINS
TO MOVE INTO THE REGION, ESPECIALLY AFTER 06Z. THIS WILL BRING A
CHANCE OF SNOW BY 12Z IN THE WESTERN PART OF THE FORECAST AREA. THE
LOWER LEVEL MOISTURE WILL BE THE MAIN CONCERN AS THE POPS ARE DRAWN
ROUGHLY WHERE THE 850 MB MOISTURE IS ABOVE 50%. HOWEVER, THIS COULD
JUST AS EASILY BE NOTHING UNTIL THE DAY ON SATURDAY, IF THE ATMOSPHERE
DOESN`T SATURATE FAST ENOUGH.
SATURDAY...THE WARM FRONT MOVES NORTH A BIT, BUT FOR THE MOISTURE
PART ONCE IT GETS TO AROUND THE STRAITS, IT LOOKS LIKE IT TRAVELS
EAST, WITH THE SFC LOW FOLLOWING ALONG IT. THIS SETS UP SNOW IN E
UPPER, WHICH COULD HAVE LIGHT TO MODERATE AMOUNTS THROUGH THE DAY.
WOULD EXPECT A MIX, ESPECIALLY BETWEEN M-32 AND THE STRAITS AS THE
PROFILES ARE EITHER ON THE 0C LINE. SOUTH OF M-32, THINK THAT IT
WILL BE MAINLY RAIN. OVERNIGHT, THE WARMER AIR WITH BOTH MODELS,
GETS TO THE STRAITS, THE RAIN WILL LIKELY GET ALL THE WAY TO THE
STRAITS, AND WE`LL GET A MIX IN E UPPER. THE CONCERN, BASED ON THE
PROFILES OF BOTH MODELS, IS THAT WE WILL PARTIALLY MELT SOME OF
THE SNOW (TEMPERATURES IN THE PROFILE GET TO +2C AROUND 850 MB
THEN FALL TO OR BELOW 0C IN E UPPER). SO WILL GO WITH SNOW/RAIN OR
FREEZING RAIN MIX AT THIS POINT, AND KEEP IT MENTIONED IN HWOAPX.
THE COLD AIR MOVES INTO E UPPER AGAIN ONCE THE LOW MOVES EAST. SO
E UPPER WILL SEE A CHANGE OVER AGAIN BETWEEN 06Z AND 12Z.
EXTENDED (SUNDAY THROUGH WEDNESDAY)...SUNDAY, THE MODELS MOVE THE
LOW EAST OF THE REGION AND THE COLD AIR MOVES BACK. HOWEVER, THINGS
ARE DRY ENOUGH AND WARM ENOUGH, THAT LITTLE IF NO PRECIPITATION WILL
FALL. MONDAY, LOOKS LIKE ANOTHER WAVE FORMS ON THE FRONT THAT
STALLS IT, AND EVEN ALLOWS FOR SOME WARMING. SO WILL GO WITH
CHANCE OF RAIN IN N LOWER AND A MIX IN E UPPER. TUESDAY, THE LOW
NO LONGER MOVES OUT OF THE MID MISSISSIPPI VALLEY AS THE MODELS
FOCUS DEVELOPMENT ON THE CLOSED 500 MB LOW IN THE SOUTHWEST
STATES. THIS WOULD KEEP THE SFC LOW IN TX/OK REGION WITH A WARM
FRONT/SFC TROUGH THAT IS STALLED IN THE OHIO VALLEY. OVERNIGHT,
THE GFS BEGINS TO LIFT THE 500 MB LOW INTO THE NORTHERN BRANCH.
THE ECMWF LOOKS BETTER WITH THE SLOWER LIFTING OF THE WAVE KEEPING
THE RAIN AND THE WARM FRONT ALONG OR SOUTH OF THE OHIO VALLEY.
WEDNESDAY, THINKING THAT THE GFS IS TOO WET, DUE TO THE PHASING OF
THE SYSTEMS. WOULD BE MORE INCLINED TO GO WITH THE ECMWF IDEA WITH
THE HIGH SETTLING IN OVER THE GREAT LAKES. WHICH WOULD KEEP US
DRY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 640 AM EDT THU APR 4 2013
SUMMARY: A MOISTURE-STARVED COLD FRONT WILL DROP THROUGH THE STATE
TODAY...BRINGING A LINE OF RAIN AND SNOW SHOWERS. HIGH PRESSURE
WILL BUILD IN BEHIND THIS FRONT TONIGHT...WITH SOME LAKE INDUCED
CLOUDINESS DEVELOPING.
RESTRICTIONS: EXPECT APN/TVC/MBL TO REMAIN VFR THROUGH THE UPCOMING
TAF PERIOD...WITH A BRIEF PERIOD OF MVFR STILL EXPECTED THIS
AFTERNOON /ALBEIT SOMEWHAT LATER THAN PREVIOUSLY EXPECTED/ AT PLN.
EXPECT SHRASN TO IMPACT THIS SITE WITH MVFR CIGS DEVELOPING AFTER
21Z IMMEDIATELY BEHIND THE DEPARTING COLD FRONT. THESE CLOUDS WILL
LIFT DURING THE EVENING WITH VFR CLOUDINESS /4KFT/ OVERNIGHT.
WINDS: SOUTHWEST WINDS WILL STRENGTHEN TO 15G25KTS FOR THE BY MID
MORNING AND CONTINUE THROUGH THE AFTERNOON WHILE GRADUALLY VEERING
WEST. LATE THIS AFTERNOON WILL SHIFT NORTHWESTERLY AND DIMINISH TO
AROUND 10KTS THIS EVENING AND OVERNIGHT.
LLWS: SOUTHWEST WINDS AT 1.5-2KFT STILL REACHING AROUND 40 KTS AND
GIVEN THAT THE TERMINALS REMAIN SOMEWHAT DECOUPLED FROM THIS
STRONGER FLOW ALOFT...WILL LEAVE LLWS MENTION IN THROUGH 14Z BEFORE
DAYTIME MIXING ELIMINATES ANY POTENTIAL SHEAR LAYERS.
&&
.MARINE...
ISSUED AT 420 AM EDT THU APR 4 2013
SUMMARY: A COLD FRONT WILL PUSH THROUGH NORTHERN MICHIGAN TODAY WITH
GUSTY SOUTHWEST WINDS AHEAD OF IT SHIFTING NORTHWESTERLY BEHIND IT
THIS EVENING AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION.
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH FRIDAY
NIGHT.
HEADLINES: GALE WARNING THROUGH LATE MORNING STILL LOOKS GOOD OVER
PORTIONS OF NORTHERN LAKE MICHIGAN. ELSEWHERE...WILL EXPAND SMALL
CRAFTS TO ALL ZONES FOR TODAY GIVEN ROBUST WIND FIELD AHEAD OF
APPROACHING COLD FRONT. MARGINAL SMALL CRAFT CONDITIONS CONTINUE
THROUGH TONIGHT BEFORE A BREAK IN WIND/WAVE ACTIVITY IS EXPECTED
FRIDAY. NEXT STORM SYSTEM ARRIVES SATURDAY WITH A RENEWED PERIOD OF
SMALL CRAFTS LIKELY THROUGHOUT THE NEARSHORE WATERS OF NORTHERN
MICHIGAN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
345-346.
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LMZ341-342-344.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ321-
322.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
614 AM EDT THU APR 4 2013
.SYNOPSIS...
ISSUED AT 420 AM EDT THU APR 4 2013
A COLD FRONT WILL MOVE THROUGH NORTHERN MICHIGAN TODAY.
PRECIPITATION ASSOCIATED WITH THIS FRONT WILL START AS SNOW THIS
MORNING...BUT MIX WITH RAIN AS THE TEMPERATURES RISE ABOVE
FREEZING TODAY. THE RAIN WILL END IN THE AFTERNOON AS DRIER TAKES
OVER BEFORE THE FRONT MOVES THROUGH. HIGH PRESSURE AND COOLER
TEMPERATURES WILL SETTLE IN FOR THURSDAY NIGHT AND FRIDAY BEFORE A
STORM SYSTEM MOVES INTO NORTHERN MICHIGAN AND HANGS AROUND FOR
MUCH OF THE WEEKEND...BRINGING RAIN AND SNOW MIXED FOR SATURDAY
AND SUNDAY.
&&
.UPDATE...
ISSUED AT 607 AM EDT THU APR 4 2013
CHANGES THIS HOUR: HAVE CONTINUED SLOWING TREND OF POPS THROUGH
MUCH OF TODAY GIVEN RECENT GOOD AGREEMENT BETWEEN THE NAM/RAP/HRRR
GIVEN VERY IMPRESSIVE PERFORMANCE FROM THE RAP OVER THE PAST FEW
HOURS. SNOWFALL HAS ARRIVED FROM SAW-ERY-ANJ AND WILL GO AHEAD AND
BUMP UP NEAR TERM POPS TO CATEGORICAL FOR NORTHERN CHIPPEWA
THROUGH DAYBREAK. BEYOND THIS...INITIAL SURGE OF ISENTROPIC ASCENT
ALONG LLEVEL MOISTURE AXIS WILL SHIFT EAST AND WE/LL THEN AWAIT
FURTHER DEVELOPMENT ALONG THE FRONTAL BOUNDARY ITSELF...WHICH IS
NOW SLIDING SOUTHEAST THROUGH WESTERN UPPER. DON/T EXPECT THIS TO
BE SUBSTANTIAL...AND AS PREVIOUSLY MENTIONED...EXPECT IT TO
DWINDLE AS IT HEADS SOUTH...WITH RAIN GRADUALLY TAKING OVER AS THE
PREDOMINATE PRECIPITATION TYPE.
COULD SEE AN INCH OF MORNING ACCUMS FROM PARADISE TO ANJ /WEBCAMS
SHOW A COATING ATTM/...SO WATCH OUT FOR SOME SLICK AM TRAVEL IN
THESE SPOTS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 420 AM EDT THU APR 4 2013
HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WINDS OVER MUCH OF
NORTHERN LAKE MICHIGAN THROUGH MID MORNING. WILL LIKELY HAVE SOME
COASTAL WIND GUSTS ABOVE 30 MPH TODAY...OTHERWISE...NO HIGH
IMPACT WEATHER EXPECTED.
OVERVIEW: SURFACE MAP EARLY THIS MORNING REVEALS HIGH PRESSURE
RESPONSIBLE FOR THE BEAUTIFUL /ALBEIT CHILLY/ AFTERNOON YESTERDAY
HAVING PUSHED SOUTH AND EAST INTO THE OHIO VALLEY/MID ATLANTIC
REGION...THIS HAS ALLOWED BROAD SOUTHWESTERLY FLOW TO DEVELOP BETWEEN
THIS FEATURE AND RATHER IMPRESSIVE SURFACE LOW NOW TRAVELING FROM
WEST TO EAST ACROSS NORTHERN ONTARIO. PRIMARY FEATURE OF NOTE
THROUGH THE SHORT TERM PORTION OF THE FORECAST IS A COLD FRONT
DRAPED TO THE SOUTH AND WEST OF THIS LOW...APPROACHING LAKE SUPERIOR
AS OF THIS WRITING. STRENGTHENING SOUTHWESTERLY WINDS OVER NORTHERN
MICHIGAN HAVE PRECLUDED STEEP TEMPERATURE FALLS OVERNIGHT WITH MOST
LOCATIONS AT LEAST 10F WARMER THAN 24 HOURS AGO. LLEVEL MOISTURE
HAS NOT RESPONDED IN TANDEM...WITH 00Z APX RAOB SHOWING A PALTRY
0.14" PWAT. CLOSER TO THE FRONT...HOWEVER...PRECIPITATION ECHOES
HAVE BEEN BLOSSOMING OVER THE PAST COUPLE OF HOURS AS ROBUST LOW
LEVEL JET AT H8 /50KTS+/ TRANSPORTS A PLUME OF 2/3" PWATS RAPIDLY
EASTWARD.
THROUGH DAYBREAK: WINDS CONTINUE TO RAMP UP FROM WEST TO EAST...WITH
SLOWLY INCREASING MID AND UPPER LEVEL CLOUDINESS...PRIMARILY FROM THE
STRAITS NORTH. TIMING AREA OF INCREASING RADAR ECHOES SUGGESTS
PRECIPITATION COULD ARRIVE AS EARLY AS 5-6AM OVER EASTERN UPPER AS
SOME SNOW SHOWERS. INTERESTING TO NOTE SURFACE DEWPOINT TREND OVER
THE PAST FEW HOURS OVER NORTHERN LOWER...WITH VALUES PLUMMETING TO
BELOW 10F AT TVC/CAD AND ROPPING EVERYWHERE AWAY FROM LAKE
MICHIGAN. THIS SUGGESTS THE SLOWING TREND IN FRONTAL PRECIP
ARRIVAL /SEEN IN RECENT RENDTIONS OF THE HRRR/RAP/ ARE LIKELY ON
THE RIGHT TRACK.
TODAY: COLD FRONT PUSHES THROUGH NORTHERN MICHIGAN TODAY...STARTING
THE DAY OVER WESTERN UPPER AND REACHING MY SOUTHEASTERN ZONES BY
EVENING. PRIMARY CONCERNS TODAY CENTER AROUND PRECIPITATION
CHANCES AS THIS BOUNDARY MOVES THROUGH...AS WELL AS THE STRENGTH
OF SOUTHWESTERLY WINDS AHEAD OF IT.
TRAJECTORY ANALYSIS SHOWS LLEVEL SOURCE REGION FOR AIR OVER NORTHERN
LOWER TODAY COMES FROM THE IOWA/ILLINOIS REGION 24 HOURS AGO...AN
AREA FEATURING A DEARTH OF LLEVEL MOISTURE. SO...BOUNDARY WILL BE
FIGHTING INCREASINGLY DRY ATMOSPHERE AS IT PUSHES SOUTH AND EAST
WITH LLEVEL MOISTURE TONGUE THINNING. LLEVEL CONVERGENCE IS
MODEST...BUT WILL HAVE SOME HELP FROM AN ARRIVING JET MAX /AND ITS
ASSOCIATED RIGHT ENTRANCE REGION/ AS WELL AS CONTINUED ISENTROPIC
ASCENT. NET RESULT: EXPECT A BROKEN LINE OF SHOWERS TO SINK SOUTH
DURING THE DAY...WEAKENING AS THEY DO SO. RECENT MODEL TRENDS HAVE
CONTINUED TO SLOW THE SOUTHWARD MOVEMENT OF ANY PRECIPITATION...
AND WHILE THIS FORECAST REPRESENTS A SLOWING TREND...IT COULD
REQUIRE FURTHER SLOWING WITH PRECIITATION POTENTIALLY COMPLETELY
FALLING APART BEFORE MAKING IT MUCH SOUTH OF M-32.
PTYPE: STARTS THE DAY ALL SNOW...BUT RAPIDLY WARMING SURFACE LAYER
SUGGESTS PREDOMINATE TYPE TO SWITCH TO RAIN COASTAL LOCALES BY LATE
MORNING AND ALL AREAS BY AFTERNOON. ONLY CAVEAT TO THIS WILL BE
OVER THE INTERIOR HIGH SPOTS WHERE WET BULBS IN THE MID 30S INDICATE
A FEW SNOWFLAKES MIGHT MIX IN AT ANY TIME...ESP IF PRECIPITATION
RATES ARE DECENT. OVERALL VERY LITTLE IMPACT EXPECTED...HOWEVER...
OUTSIDE OF A FEW SLICK SPOTS TO START THE DAY FROM THE BRIDGE
NORTH. PAVEMENT TEMPS WILL BE TOO WARM TO SUPPORT ANY ICING BY MID
MORNING OVER NORTHERN LOWER.
WINDS: PRETTY MUCH FULLY FORCED BY THE STRENGTH OF THE LOW LEVEL
JET /40-50KTS AT H9 EARLY...WEAKENING AS IT HEADS SOUTH/ AND THE
AMOUNT OF MIXING WE CAN DEVELOP AHEAD OF THE BOUNDARY. GIVEN A
SOMEWHAT SLOWER ARRIVAL TO THE BOUNDARY...MIXING HEIGHTS SHOULD GET
A CHANCE TO BUILD EARLY...WITH MOMENTUM TRANSPORT SUGGESTING WE CAN
LIKELY TAP 30KTS. SO...EXPECT SOUTHWEST WINDS 15-25 MPH WITH GUSTS
OVER 30 MPH BY LATE MORNING AND THROUGH THE AFTERNOON OVER
NORTHERN LOWER...A LITTLE WEAKER THAN THIS FURTHER NORTH.
TEMPS: T9 ROCKETS TO JUST ABOVE FREEZING AHEAD OF THE BOUNDARY...
WITH THE POTENTIAL TO PRODUCE LOW-MID 50S AHEAD OF THE BOUNDARY.
COMPLICATING THIS WILL BE CLOUDS AND PRECIP...WHICH...WITH PRETTY
SUBSTANTIAL LLEVEL DEWPOINT DEPRESSIONS SUGGESTS AMPLE OPPORTUNITY
FOR EVAPORATIONAL COOLING. WILL ALLOW SOUTHEASTERN ZONES TO MAKE A
RUN AT 55...WITH LOCALES NORTH OF THIS GENERALLY IN THE MID-UPPER
40S.
TONIGHT: NORTHWEST WINDS WILL USHER COLDER AIR INTO THE REGION AS
HIGH PRESSURE BUILDS IN FROM THE NORTHERN PLAINS. T8 FALLS TO -12C
SOUTH/-15C NORTH AFTER MIDNIGHT...WHICH WITH A MINOR AMOUNT OF
RESIDUAL 850-700MB MOISTURE SUGGESTS THAT SOME LAKE RESPONSE MAY TRY
AND GET GOING...BUT NOT UNTIL THE VERY END OF THIS PERIOD. WILL
CARRY CHANCE POPS AFTER 09Z BUT NO SIGNIFICANT SNOWFALL EXPECTED.
TEMPERATURES LOOK TO FALL INTO THE MID 20S AS COLD AIR ADVECTION IS
OFFSET SOMEWHAT BY RESIDUAL WINDS AND SOME LAKE CLOUDINESS /NORTH/.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM EDT THU APR 4 2013
FRIDAY...INITIALLY, THERE WILL BE SOME LIGHT SNOW AND FLURRIES IN E
UPPER, MAINLY NEAR WHITEFISH POINT AS THE 850 MB TEMPERATURES FALL
TO AROUND -14C WITH ABOUT 50% RH IN THE 850-700 MB LAYER. THIS WILL
BE MAINLY IN THE MORNING, BECAUSE AS THE HIGH PRESSURE BUILDS INTO
THE REGION MORE DRY AIR PUSHES INTO THE FORECAST AREA, AND THE 850
MB TEMPERATURES RISE ABOVE -12C BY 18Z. SO WILL GO WITH A DRY DAY
OVERALL.
FRIDAY NIGHT...THE WARM ADVECTION WING FROM THE NEXT SYSTEM BEGINS
TO MOVE INTO THE REGION, ESPECIALLY AFTER 06Z. THIS WILL BRING A
CHANCE OF SNOW BY 12Z IN THE WESTERN PART OF THE FORECAST AREA. THE
LOWER LEVEL MOISTURE WILL BE THE MAIN CONCERN AS THE POPS ARE DRAWN
ROUGHLY WHERE THE 850 MB MOISTURE IS ABOVE 50%. HOWEVER, THIS COULD
JUST AS EASILY BE NOTHING UNTIL THE DAY ON SATURDAY, IF THE ATMOSPHERE
DOESN`T SATURATE FAST ENOUGH.
SATURDAY...THE WARM FRONT MOVES NORTH A BIT, BUT FOR THE MOISTURE
PART ONCE IT GETS TO AROUND THE STRAITS, IT LOOKS LIKE IT TRAVELS
EAST, WITH THE SFC LOW FOLLOWING ALONG IT. THIS SETS UP SNOW IN E
UPPER, WHICH COULD HAVE LIGHT TO MODERATE AMOUNTS THROUGH THE DAY.
WOULD EXPECT A MIX, ESPECIALLY BETWEEN M-32 AND THE STRAITS AS THE
PROFILES ARE EITHER ON THE 0C LINE. SOUTH OF M-32, THINK THAT IT
WILL BE MAINLY RAIN. OVERNIGHT, THE WARMER AIR WITH BOTH MODELS,
GETS TO THE STRAITS, THE RAIN WILL LIKELY GET ALL THE WAY TO THE
STRAITS, AND WE`LL GET A MIX IN E UPPER. THE CONCERN, BASED ON THE
PROFILES OF BOTH MODELS, IS THAT WE WILL PARTIALLY MELT SOME OF
THE SNOW (TEMPERATURES IN THE PROFILE GET TO +2C AROUND 850 MB
THEN FALL TO OR BELOW 0C IN E UPPER). SO WILL GO WITH SNOW/RAIN OR
FREEZING RAIN MIX AT THIS POINT, AND KEEP IT MENTIONED IN HWOAPX.
THE COLD AIR MOVES INTO E UPPER AGAIN ONCE THE LOW MOVES EAST. SO
E UPPER WILL SEE A CHANGE OVER AGAIN BETWEEN 06Z AND 12Z.
EXTENDED (SUNDAY THROUGH WEDNESDAY)...SUNDAY, THE MODELS MOVE THE
LOW EAST OF THE REGION AND THE COLD AIR MOVES BACK. HOWEVER, THINGS
ARE DRY ENOUGH AND WARM ENOUGH, THAT LITTLE IF NO PRECIPITATION WILL
FALL. MONDAY, LOOKS LIKE ANOTHER WAVE FORMS ON THE FRONT THAT
STALLS IT, AND EVEN ALLOWS FOR SOME WARMING. SO WILL GO WITH
CHANCE OF RAIN IN N LOWER AND A MIX IN E UPPER. TUESDAY, THE LOW
NO LONGER MOVES OUT OF THE MID MISSISSIPPI VALLEY AS THE MODELS
FOCUS DEVELOPMENT ON THE CLOSED 500 MB LOW IN THE SOUTHWEST
STATES. THIS WOULD KEEP THE SFC LOW IN TX/OK REGION WITH A WARM
FRONT/SFC TROUGH THAT IS STALLED IN THE OHIO VALLEY. OVERNIGHT,
THE GFS BEGINS TO LIFT THE 500 MB LOW INTO THE NORTHERN BRANCH.
THE ECMWF LOOKS BETTER WITH THE SLOWER LIFTING OF THE WAVE KEEPING
THE RAIN AND THE WARM FRONT ALONG OR SOUTH OF THE OHIO VALLEY.
WEDNESDAY, THINKING THAT THE GFS IS TOO WET, DUE TO THE PHASING OF
THE SYSTEMS. WOULD BE MORE INCLINED TO GO WITH THE ECMWF IDEA WITH
THE HIGH SETTLING IN OVER THE GREAT LAKES. WHICH WOULD KEEP US
DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 132 AM EDT THU APR 4 2013
SUMMARY: A COLD FRONT WILL PUSH SOUTHEAST THROUGH THE GREAT LAKES
REGION TODAY...BRINGING A BAND OF SCATTERED RAIN AND SNOW SHOWERS
ALONG WITH GUSTY SOUTHWEST WINDS. SKIES WILL PARTIALLY CLEAR BEHIND
THE FRONT THIS EVENING AS HIGH PRESSURE BUILDS TOWARDS THE GREAT
LAKES FROM CENTRAL CANADA.
RESTRICTIONS: REALLY NOT THAT EXCITED ABOUT RESTRICTION POTENTIAL
WITH THIS BOUNDARY AS LLEVEL AIRMASS IS QUITE DRY. INHERITED TAFS
INCLUDED PERIOD OF MVFR AT PLN AND THIS LOOKS LIKE A GOOD WAY TO GO
WITH THE LLEVEL MOISTURE GRADUALLY ERODING AS THE BOUNDARY HEADS
SOUTH. THUS...AT APN/TVC/MBL EXPECT A VFR TAF PERIOD WITH A CHANCE
OF AN AFTERNOON RAIN SHOWER. AT PLN...CHANCES FOR A SHOWER /RAIN OR
SNOW/ ARE MORE LIKELY AND WILL CONTINUE BRIEF PERIOD OF MVFR. VFR
CONDITIONS /RESIDUAL 4KFT CLOUD DECK/ TAKE OVER BEHIND THE FRONT
THIS EVENING.
WINDS: LIGHT WINDS WILL BECOME SOUTHWESTERLY 5-10KTS TOWARDS
DAYBREAK BEFORE INCREASING MARKEDLY TO 15G25KTS FOR THE LATE
MORNING/EARLY AFTERNOON. BEYOND THIS...WINDS WILL SHIFT
NORTHWESTERLY AND DIMINISH TO AROUND 10KTS THIS EVENING.
LLWS: IMPRESSIVE LOW LEVEL JET AHEAD OF ARRIVING FRONT WILL ALLOW
FOR THE DEVELOPMENT OF LLWS LATER TONIGHT AT ALL SITES WITH 1.5KFT
WINDS INCREASING TO 40 KTS FROM THE SOUTHWEST. WIND SHEAR WILL
ABATE DURING THE MORNING HOURS AS MIXING COMMENCES.
&&
.MARINE...
ISSUED AT 420 AM EDT THU APR 4 2013
SUMMARY: A COLD FRONT WILL PUSH THROUGH NORTHERN MICHIGAN TODAY WITH
GUSTY SOUTHWEST WINDS AHEAD OF IT SHIFTING NORTHWESTERLY BEHIND IT
THIS EVENING AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION.
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH FRIDAY
NIGHT.
HEADLINES: GALE WARNING THROUGH LATE MORNING STILL LOOKS GOOD OVER
PORTIONS OF NORTHERN LAKE MICHIGAN. ELSEWHERE...WILL EXPAND SMALL
CRAFTS TO ALL ZONES FOR TODAY GIVEN ROBUST WIND FIELD AHEAD OF
APPROACHING COLD FRONT. MARGINAL SMALL CRAFT CONDITIONS CONTINUE
THROUGH TONIGHT BEFORE A BREAK IN WIND/WAVE ACTIVITY IS EXPECTED
FRIDAY. NEXT STORM SYSTEM ARRIVES SATURDAY WITH A RENEWED PERIOD OF
SMALL CRAFTS LIKELY THROUGHOUT THE NEARSHORE WATERS OF NORTHERN
MICHIGAN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
345-346.
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LMZ341-342-344.
LS...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ321-
322.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...JL
SHORT TERM...ARNOTT
LONG TERM...JL
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
721 PM CDT FRI APR 5 2013
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 358 PM CDT FRI APR 5 2013
EARLY APRIL SNOW SHOWERS ACROSS THE NORTHERN HALF OF THE FORECAST
AREA THIS AFTERNOON. WE KNEW THERE WAS POTENTIAL FOR A FEW FLAKES
GIVEN THE DRY AIR MASS IN PLACE...BUT THAT CAN BE A DOUBLE EDGED
SWORD IN THAT YOU SOMETIMES END UP WITH MORE VIRGA AND LITTLE
PRECIP. NONETHELESS...WE SEE WHAT CAN HAPPEN WHEN YOU PRECIP INTO
A REALLY DRY COLUMN. 0-1 KM WET BULB TEMPS WERE GENERALLY 1-2 C
ACROSS THE AREAS RECEIVING SNOW THIS AFTERNOON. MANY SITES WERE
BETWEEN 40-43 DEGREES WITH A DEWPOINT OF 18-20 EARLY THIS
AFTERNOON. WITHIN 30-60 MINUTES THIS AFTERNOON...TEMPS HAVE COOLED
6-8 DEGREES AND NOW SIT IN THE LOWER TO MID 30S IN MANY LOCATIONS
WITH A HEALTHY DUSTING OF SNOW ON GRASSY SURFACES. THE PRECIP
REACHING THE GROUND ACROSS PORTIONS OF THE SOUTH TWIN CITIES METRO
AND SOUTHERN MN HAS BEEN A MIXTURE OF LIGHT RAIN/SNOW. THE
SNOWBAND IS EXPECTED TO MOVE OUT ABOUT BETWEEN AN HOUR OR TWO
AFTER BEGINNING...SO MOST OF THE LIGHT SNOW WILL BE CONFINED TO
WEST CENTRAL AFTER 5-6 PM. THE TEMPS WILL NOT CLIMB BACK TO PRE-
SNOW LEVELS AFTER IT ENDS...BUT A RISE OF A COUPLE DEGREES IS
POSSIBLE THIS EVENING. ROADS SHOULD LARGELY REMAIN WET. IN
FACT...AS THE PRECIP RATES DECREASE...SITES THAT HAVE SEEN SNOW
COULD ACTUALLY SWITCH BACK TO RAIN LATE THIS AFTERNOON. UPSTREAM
OBSERVATIONS SUPPORT THIS.
LOW PRESSURE IS RAPIDLY DEVELOPING IN THE NORTHERN PLAINS THIS
AFTERNOON. 05.21Z MSAS IS ANALYZING AN 11 MN MSLP PRESSURE FALL IN
NORTHERN CENTRAL NE. THE SURFACE LOW IS EXPECTED TO TRACK BETWEEN
THE TWIN CITIES METRO AREA AND THE MN/IA BORDER. THE 05.12Z GFS IS
FARTHER NORTH...WHILE THE 12Z NAM/ECMWF TAKE THE LOW NEAR THE
MN/IA BORDER. REGARDLESS OF THE PRECISE PATH...THE BEST 700-600
FGEN SIGNAL AND HIGHEST SWATH OF QPF WILL BE JUST NORTH OF THE
FORECAST AREA...VERY NEAR WHERE THE CURRENT WINTER WEATHER
ADVISORY HAS BEEN ISSUED. WHILE A SLUSHY INCH OR TWO OF SNOW IS
POSSIBLE...ESPECIALLY ALONG A LINE FROM ALEXANDRIA...TO LITTLE
FALLS...TO RICE LAKE IN WI...WE THINK MOST OF SOUTHERN AND CENTRAL
MN AND WEST CENTRAL WI WILL TRANSITION TO RAIN TONIGHT. THIS MAY
BE SOME WHAT COUNTER INTUITIVE WITH NIGHTFALL APPROACHING...BUT AS
THE SURFACE LOW APPROACHES...925MB TO 850MB TEMPS MAKE A BIG JUMP
AROUND 06Z. AS MENTIONED ABOVE THE NOSE OF THE WARM AIR ADVECTION
AND FGEN WILL BE JUST NORTH OF THE FORECAST AREA...SO DON`T THINK
THERE WILL BE MUCH PRECIP TONIGHT. CONVERGENCE RIGHT NEAR THE
SURFACE LOW COULD KICK UP A EFW SHOWERS TONIGHT AND FOR THE FIRST
HALF OF SATURDAY...BUT MOST LOCATIONS COULD END UP SEEING LESS
THAN A TENTH INCH ACROSS SOUTHERN MN. A QUARTER TO HALF INCH IS
STILL EXPECTED ACROSS PORTIONS OF CENTRAL MN AND WEST CENTRAL WI.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 358 PM CDT FRI APR 5 2013
WE WILL HAVE A BIT OF LULL IN WHAT IS SHAPING UP TO BE A VERY
ACTIVE PATTERN OVER THE NEXT WEEK ON SUNDAY. A SURFACE RIDGE MOVES
OVERHEAD AND GIVES US A BRIEF REPRIEVE IN THE PRECIP BEFORE A
PACIFIC NORTHWEST TROUGH COMES SWINGING ACROSS THE ROCKIES SUNDAY
NIGHT. INCREASING SOUTHWEST FLOW ALOFT INTO THE UPPER MISSISSIPPI
RIVER VALLEY REGION AND DEVELOPING LOW PRESSURE WILL BRING A BROAD
AREA OF MOISTURE TRANSPORT ACROSS THE PLAINS. THE 12Z ECMWF AND
12Z GFS HAVE QUITE DIFFERENT SOLUTIONS FOR THE MOVEMENT AND
IMPACT OF THE SOUTHWEST US UPPER LOW AND ASSOCIATED SURFACE
SYSTEM. THE ECMWF APPEARS TO HAVE BETTER RUN TO RUN CONSISTENCY
AND THE EC IS KEEPING THE SURFACE WARM FRONT SOUTH OF IOWA AND A
SLOWER PROGRESSION OF THE OVERALL SYSTEM. THE GFS DEVELOPS A
SURFACE FARTHER NORTH AND PUSHES THE SYSTEM EAST MUCH QUICKER.
STILL USING A BLEND OF THE 12Z MODEL SOLUTIONS AND THE ONGOING
FORECAST WHICH YIELDS A PROLONGED PERIOD OF POPS AND CLOUDY AND
COOL WEATHER. FORECAST SOUNDINGS ALSO INDICATE MIXED PRECIPITATION
AND THE CHANCE FOR SNOW...ESPECIALLY ACROSS THE NORTHERN FORECAST
AREA WITH THE NEXT TWO WAVES OF MOISTURE. MODEL CONSENSUS AND THE
WPC QPF ALL INDICATE THE POTENTIAL FOR 0.50-2.00" OF TOTAL LIQUID
OVER THE NEXT 5-6 DAYS. THIS...COMBINED WITH SNOW MELT...WILL
CONTINUE TO KEEP THE THREAT FOR AT LEAST MINOR FLOODING ON OUR RADAR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 721 PM CDT FRI APR 5 2013
THE POWER OF THE WET BULBING EFFECT IN FULL DISPLAY TODAY...AS
LEAD BAND OF WARM ADVECTIVE PRECIP HAS QUICKLY COOLED THE AIR DOWN
TO ALLOW A QUICK BURST OF SNOW TO FALL. ONLY TERMINALS LEFT TO
SEE THIS SNOW ARE IN WI AND BASED TIMING ON HOW PRECIP HAS PLAYED
OUT AT LOCATIONS TO THE WEST THIS AFTERNOON. BEHIND THIS BAND OF
PRECIP...DRY LOW LEVEL AIR QUICKLY MOVES BACK IN...WITH A
PROLONGED PERI0D OF VFR CONDS EXPECTED UNTIL SFC LOW BEGINS MOVING
INTO SW MN AFTER 9Z. THIS SFC LOW IS EXPECTED TO MOVE NEARLY OVER
RWF/MSP/RNH/EAU...WITH HEAVIEST PRECIP EXPECTED AT AXN/STC AS A
RESULT PER THE NAM. IN FACT OUTSIDE OF AXN/STC...MAY NOT SEE MUCH
MORE THAN DZ THE REST OF THE WAY. BASED ON CURRENT CONDS...GFSLAMP
LOOKS WAY TO MOIST AGAIN...SO FOLLOWED THE RAP THEN NAM FOR
BRINGING BACK LOW CIGS SAT MORNING. NOT ANTICIPATING ANY SUB VFR
CIGS UNTIL THE SFC LOW MOVES OVERHEAD...WITH LOWER CIGS CONTINUING
IN ITS WAKE. IN FACT...IF THE CURRENT RAP/HRRR ARE TO BE
BELIEVED...CURRENT TAFS MAY BE TOO AGGRESSIVE WITH BRINGING LOWER
CONDITIONS IN SAT MORNING. FOR WINDS...WITH SFC LOW MOVING
OVERHEAD...LAMP WINDS IN EXCESS OF 10KTS THE WHOLE PERIOD WERE WAY
OVERDONE...SO STUCK CLOSE TO WHAT IS ON OUR GRIDS FOR THE WIND
FORECAST IN THESE TAFS. BASICALLY...ANTICIPATE STRONG SE WINDS
TONIGHT...GIVING WAY TO LIGHT WINDS IN THE MORNING THAT WILL BACK
OVER TO THE NW AT STC/AXN AND VEER THROUGH THE SOUTH ON THEIR WAY
TO THE WNW AT OTHER TERMINALS.
KMSP...CONFIDENCE IN FORECAST HIGH THROUGH ABOUT 12Z...WITH VFR
CONDITIONS EXPECTED...BUT BEGINS TO DIMINISH AS SFC LOW MOVES IN.
BASED THE LOWERING OF THE CIGS ON THE NAM...THOUGH THE RAP/HRRR
CERTAINLY CAST SOME DOUBT ON SEEING ANY LOWER CIGS BEFORE 15Z.
WORST CONDITIONS SHOULD BE SEEN AS SFC LOW MOVES OVERHEAD...WITH
NOT MUCH WORSE THAN -RA OR DZ EXPECTED...BUT THE WEAKER WINDS
UNDER THE LOWER SHOULD FINALLY ALLOW CIGS TO LOWER...WITH VIS
DROPPING AS WELL WITH HZ/BR. NAM HAS STRONG COLD ADVECTION THROUGH
ABOUT 00Z...BUT QUICKLY STARTS TO DIMINISH THE COLD ADVECTION AFTER
THAT...SO MAY VERY WELL SEE CIGS IMPROVE BACK TO VFR PRIOR TO THE
END OF THIS TAF. FOR WINDS...LOW LOOKS TO BE NEARLY OVERHEAD AT
18Z...SO WINDS BETWEEN 16Z AND 20Z MAY END UP BEING QUITE VARIABLE
AS WE TRANSITION FROM SE WINDS OVER TO WNW WINDS.
/OUTLOOK FOR KMSP/
SUN...VFR WITH MVFR OR LOWER WITH -RA POSSIBLE LATE. WIND NW 5-10KTS
BCMG SE.
MON...MVFR OR LOWER WITH -RA LIKELY IN MORNING. WIND ENE 5-10KT.
TUE...MVFR OR LOWER POSSIBLE. CHANCE -RA. WIND NE 10G20KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
620 AM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE PASSES SOUTH LATE TODAY AND TONIGHT WITH THE CHANCE FOR
RAIN. MODERATING TEMPERATURES OVER THE WEEKEND. FRONT NEARBY SUNDAY
INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
615 AM UPDATE...
NO CHANGES ATTM.
PREVIOUS DISCUSSION BELOW...
MDLS COMING IN A BIT FASTER WITH ONSET OF PCPN LATER TDY AS SFC
LOW ORGANIZES ALONG GA/SC COAST. HOWEVER VERY DRY LLVLS WILL BE
BATTLING MOISTURE ADVECTION FROM S. AS SUCH DID NOT GO AS FAST AS
MDLS SUGGEST ONCE INTO S WV PLATEAU. LATEST RAP MDL SEEMS TO HAVE
A BETTER REFLECTION OF CURRENT THINKING AND USED IT AS A GUIDE
THRU 00Z. DO BRING IN HIGH POPS ACROSS SW VA BY 18Z AND THEN
SLOWLY SPREAD N UP THE EASTERN SLOPES TO INCLUDE MUCH OF
POCAHONTAS CO WITH THE CATEGORICAL POPS. HAVE A SHARP GRADIENT
HEADING W...WITH CHC POPS EXTENDING TO CRW- HTS AREA AND UP TOWARD
CKB. FEEL SE OH AND NW LOWLAND CO STAY DRY. HAVE ARND A THIRD OF
AN INCH QPF FOR SW VA AND UP THE EASTERN SLOPES. QUICKLY TAILS OF
W OF I79 CORRIDOR. EXIT BULK OF PCPN BY 06Z TO THE E...WITH
LINGERING CHC POPS FOR S/W TROF AXIS SLIDING THRU.
THERE IS SOME CONCERN FOR WINTRY PCPN AT THE ONSET ACROSS RIDGES
IN POCAHONTAS CO. MDLS INDICATE GOOD WET BULBING ARND 00Z TO
REFLECT SOME WET SN OR MIX POTENTIAL BEFORE SWITCHING TO RA LATER
IN EVE. USED SFC AND MODEL ALOFT TOO TO REFLECT THIS IN WX GRIDS.
WILL KEEP ACCUMULATIONS OUT OF GRIDS FOR NOW THOUGH.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS IN GOOD AGREEMENT SHOWING SYSTEM PULLING OFF TO THE EAST
EARLY FRIDAY...WITH DRY WEATHER EXPECTED BY MIDDAY. WILL SPEED UP
THE EXODUS OF THE POPS. MOS GUIDANCE FOR HIGHS ON FRIDAY HAS BEEN
TRENDING DOWNWARD...BUT STILL LOOKS TOO HIGH. HAVE UNDERCUT MOS ONCE
AGAIN FOR HIGHS FRIDAY...AND ALSO ON SATURDAY.
A COLD FRONT THEN PUSHES INTO THE AREA ON SUNDAY...BEFORE STALLING
OVER THE AREA. SOME DEBATE AMONG THE MODELS ON WHERE THE FRONT WILL
STALL. CURRENT FORECAST LOOKS LIKE A GOOD COMPROMISE FOR NOW...SO
DID NOT CHANGE WITH THE EXCEPTION OF SLOWING THE ARRIVAL OF THE
SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
WAVY FRONT APPROACHES THIS WEEKEND AND THEN HANGS NEARBY THE
BALANCE OF THE PERIOD. RIDGING ADVERTISED FOR EARLY NEXT WEEK OVER
THE PAST FEW DAYS IS ALL BUT GONE...THE GFS STILL AMPLIFYING ONE BUT
ALONG THE E COAST TUE. THAT IS WHEN THE ECMWF IS MARKEDLY DIFFERENT
WITH THE NORTHERN STREAM OVER CANADA...USING EASTERN CANADIAN
TROUGHING TO SINK THE CONFLUENCE...AND FRONTAL ZONE...SWD. THIS
WOULD MAKE THE LATTER PORTION OF THE FCST MUCH WETTER AND COOLER
THAN CURRENTLY CODED. AS PER HPC...IT AND TELECONNECTIONS DEPENDENT
UPON SW CONUS TROUGH WILL PLAY A ROLE IN HOW FAR N THE FRONT IS OVER
THE EASTERN CONUS DAYS 6-7.
DRY WEATHER GIVES WAY TO INCREASING CHANCE FOR SHOWERS NW TO SE DAY
3 NT AND DAY 4 WITH INITIAL APPROACH OF FRONT AND INITIAL UPPER
LEVEL WAVE. KEEP CHANCE THROUGH THE BALANCE OF THE FCST...HIGHEST N
AND NW...LOWEST S AND SE...HAVE HAVE JUST SLIGHT CHANCE EARLY ON.
MORE OR LESS EQUAL CHANCE FOR PRECIPITATION THROUGHOUT THE AREA DAY
7. ALSO INTRODUCED SLIGHT CHANCE FOR THUNDER DURING THE AFTERNOONS
AND EARLY EVENINGS BEGINNING MON AS DEW POINTS INCREASE TO NEAR 50.
BLENDED IN ADJMEXBC FOR HIGHS EARLY ON AND THEN HPC DAYS 6 AND 7
HIGHS AND ALL LOWS. ADJMEXBC APPEARED TOO LOW ON LOWS GIVEN SW
FLOW...RISING DEW POINTS AND CLOUDS.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
12Z THURSDAY TO 12Z FRIDAY...
LIGHT SURFACE WINDS BECOMING GUSTY AGAIN AFTER 15Z...MAINLY
ACROSS THE HIGHER TERRAIN. A LOW PRESSURE SYSTEM WILL APPROACH
FROM THE SOUTH LATE TDY...ALLOWING RA TO OVERSPREAD SW VA BY 18Z
AND SLOWLY SPREADING N UP THE WV MTNS. THIS WILL CREATE GENERAL MVFR
CONDITIONS ACROSS SOUTHWEST VA 18Z...SOUTHERN WV BY 00Z... AND UP
WV MTNS BY 03Z. KEPT SOUTHEAST OHIO AND NORTHERN WV REMAINING VFR
IN MID DECK. KHTS AND KCRW TRICKY AS THEY WILL BE ON THE NW FRINGE
OF BEST LLVL MOISTURE AND PCPN. WILL KEEP THEM VFR WITH THIS
ISSUANCE BUT ALLOW CIGS TO LWR INTO LOW END VFR.
THERE MAY BE SOME FG OVERNIGHT FOR AREAS THAT RECEIVE RA AS THE LLVL
FLOW REMAINS ON THE LIGHT SIDE. HOWEVER CONFIDENCE IS NOT
PARTICULARLY HIGH TO INCLUDE IN TAFS ATTM.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: LOW PRESSURE SYSTEM MAY SPREAD MOISTURE AND
LOW CIGS FARTHER NORTH THAN CURRENTLY FORECAST TOWARDS THE END OF
THE TAF PERIOD. FG MAY DEVELOP OVERNIGHT ACROSS AREAS THAT RECEIVE RA.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z FRIDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.FIRE WEATHER...
RH VALUES WILL AGAIN DIP INTO TEENS AND 20S PERCENT WISE AS DWPTS
MIX DOWN INTO THE TEENS AND TEMPS CLIMB. MOISTURE ADV FROM S IN
AFTN SHOULD ALLOW RH TO RECOVER UP TO CENTRAL WV WITH RA ACROSS SW
VA. HOWEVER...ACROSS PORTIONS OF NE KY...SE OH AND N WV...THE DRY
AIR WILL PREVAIL TDY. SOME AFTN GUSTS ARND 15 KTS MAY ALSO BE
EXPECTED ACROSS N WV. WITH VERY DRY 10 HR FUELS IN PLACE...AN
ENHANCED FIRE DANGER THREAT MAY BE REALIZED TODAY. CONDITIONS
WILL BE MONITORED AND COORDINATED WITH THE APPROPRIATE STATE
FORESTRY PERSONNEL FOR THE POTENTIAL FOR ANY FIRE WEATHER
STATEMENTS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...TRM
AVIATION...30
FIRE WEATHER...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
330 AM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE PASSES SOUTH LATE TODAY AND TONIGHT WITH THE CHANCE FOR
RAIN. MODERATING TEMPERATURES OVER THE WEEKEND. FRONT NEARBY SUNDAY
INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MDLS COMING IN A BIT FASTER WITH ONSET OF PCPN LATER TDY AS SFC
LOW ORGANIZES ALONG GA/SC COAST. HOWEVER VERY DRY LLVLS WILL BE
BATTLING MOISTURE ADVECTION FROM S. AS SUCH DID NOT GO AS FAST AS
MDLS SUGGEST ONCE INTO S WV PLATEAU. LATEST RAP MDL SEEMS TO HAVE
A BETTER REFLECTION OF CURRENT THINKING AND USED IT AS A GUIDE
THRU 00Z. DO BRING IN HIGH POPS ACROSS SW VA BY 18Z AND THEN
SLOWLY SPREAD N UP THE EASTERN SLOPES TO INCLUDE MUCH OF
POCAHONTAS CO WITH THE CATEGORICAL POPS. HAVE A SHARP GRADIENT
HEADING W...WITH CHC POPS EXTENDING TO CRW- HTS AREA AND UP TOWARD
CKB. FEEL SE OH AND NW LOWLAND CO STAY DRY. HAVE ARND A THIRD OF
AN INCH QPF FOR SW VA AND UP THE EASTERN SLOPES. QUICKLY TAILS OF
W OF I79 CORRIDOR. EXIT BULK OF PCPN BY 06Z TO THE E...WITH
LINGERING CHC POPS FOR S/W TROF AXIS SLIDING THRU.
THERE IS SOME CONCERN FOR WINTRY PCPN AT THE ONSET ACROSS RIDGES
IN POCAHONTAS CO. MDLS INDICATE GOOD WET BULBING ARND 00Z TO
REFLECT SOME WET SN OR MIX POTENTIAL BEFORE SWITCHING TO RA LATER
IN EVE. USED SFC AND MODEL ALOFT TOO TO REFLECT THIS IN WX GRIDS.
WILL KEEP ACCUMULATIONS OUT OF GRIDS FOR NOW THOUGH.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS IN GOOD AGREEMENT SHOWING SYSTEM PULLING OFF TO THE EAST
EARLY FRIDAY...WITH DRY WEATHER EXPECTED BY MIDDAY. WILL SPEED UP
THE EXODUS OF THE POPS. MOS GUIDANCE FOR HIGHS ON FRIDAY HAS BEEN
TRENDING DOWNWARD...BUT STILL LOOKS TOO HIGH. HAVE UNDERCUT MOS ONCE
AGAIN FOR HIGHS FRIDAY...AND ALSO ON SATURDAY.
A COLD FRONT THEN PUSHES INTO THE AREA ON SUNDAY...BEFORE STALLING
OVER THE AREA. SOME DEBATE AMONG THE MODELS ON WHERE THE FRONT WILL
STALL. CURRENT FORECAST LOOKS LIKE A GOOD COMPROMISE FOR NOW...SO
DID NOT CHANGE WITH THE EXCEPTION OF SLOWING THE ARRIVAL OF THE
SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
WAVY FRONT APPROACHES THIS WEEKEND AND THEN HANGS NEARBY THE
BALANCE OF THE PERIOD. RIDGING ADVERTISED FOR EARLY NEXT WEEK OVER
THE PAST FEW DAYS IS ALL BUT GONE...THE GFS STILL AMPLIFYING ONE BUT
ALONG THE E COAST TUE. THAT IS WHEN THE ECMWF IS MARKEDLY DIFFERENT
WITH THE NORTHERN STREAM OVER CANADA...USING EASTERN CANADIAN
TROUGHING TO SINK THE CONFLUENCE...AND FRONTAL ZONE...SWD. THIS
WOULD MAKE THE LATTER PORTION OF THE FCST MUCH WETTER AND COOLER
THAN CURRENTLY CODED. AS PER HPC...IT AND TELECONNECTIONS DEPENDENT
UPON SW CONUS TROUGH WILL PLAY A ROLE IN HOW FAR N THE FRONT IS OVER
THE EASTERN CONUS DAYS 6-7.
DRY WEATHER GIVES WAY TO INCREASING CHANCE FOR SHOWERS NW TO SE DAY
3 NT AND DAY 4 WITH INITIAL APPROACH OF FRONT AND INITIAL UPPER
LEVEL WAVE. KEEP CHANCE THROUGH THE BALANCE OF THE FCST...HIGHEST N
AND NW...LOWEST S AND SE...HAVE HAVE JUST SLIGHT CHANCE EARLY ON.
MORE OR LESS EQUAL CHANCE FOR PRECIPITATION THROUGHOUT THE AREA DAY
7. ALSO INTRODUCED SLIGHT CHANCE FOR THUNDER DURING THE AFTERNOONS
AND EARLY EVENINGS BEGINNING MON AS DEW POINTS INCREASE TO NEAR 50.
BLENDED IN ADJMEXBC FOR HIGHS EARLY ON AND THEN HPC DAYS 6 AND 7
HIGHS AND ALL LOWS. ADJMEXBC APPEARED TOO LOW ON LOWS GIVEN SW
FLOW...RISING DEW POINTS AND CLOUDS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY TO 06Z FRIDAY...
LIGHT SURFACE WINDS BECOMING GUSTY AGAIN AFTER 15Z...PARTICULARLY
ACROSS THE HIGHER TERRAIN. A LOW PRESSURE SYSTEM WILL APPROACH
FROM THE SOUTH LATE TDY...ALLOWING RA TO OVERSPREAD SW VA BY 18Z
AND SLOWLY SPREADING N UP THE WV MTNS. THIS WILL CREATE GENERAL MVFR
CONDITIONS ACROSS SOUTHWEST VA 18Z...SOUTHERN WV BY 00Z... AND UP
WV MTNS BY 03Z. KEEP SOUTHEAST OHIO AND NORTHERN WV REMAINING
VFR IN MID DECK. KHTS AND KCRW TRICKY AS THEY WILL BE ON THE NW
FRINGE OF BEST LLVL MOISTURE AND PCPN. WILL KEEP THEM VFR WITH
THIS ISSUANCE BUT ALLOW CIGS TO LWR INTO LOW END VFR. KEPT SHRA
MENTION OUT OF THOSE LOCALES DUE TO LOW CHC AT THIS RANGE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: LOW PRESSURE SYSTEM MAY SPREAD MOISTURE AND
LOW CIGS FARTHER NORTH THAN CURRENTLY FORECAST TOWARDS THE END OF
THE TAF PERIOD.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 04/04/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z FRIDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.FIRE WEATHER...
RH VALUES WILL AGAIN DIP INTO TEENS AND 20S PERCENT WISE AS DWPTS
MIX DOWN INTO THE TEENS AND TEMPS CLIMB. MOISTURE ADV FROM S IN
AFTN SHOULD ALLOW RH TO RECOVER UP TO CENTRAL WV WITH RA ACROSS SW
VA. HOWEVER...ACROSS PORTIONS OF NE KY...SE OH AND N WV...THE DRY
AIR WILL PREVAIL TDY. SOME AFTN GUSTS ARND 15 KTS MAY ALSO BE
EXPECTED ACROSS N WV. WITH VERY DRY 10 HR FUELS IN PLACE...AN
ENHANCED FIRE DANGER THREAT MAY BE REALIZED TODAY. CONDITIONS
WILL BE MONITORED AND COORDINATED WITH THE APPROPRIATE STATE
FORESTRY PERSONNEL FOR THE POTENTIAL FOR ANY FIRE WEATHER
STATEMENTS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...TRM
AVIATION...30
FIRE WEATHER...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
255 AM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE PASSES SOUTH LATE TODAY AND TONIGHT WITH THE CHANCE FOR
RAIN. MODERATING TEMPERATURES OVER THE WEEKEND. FRONT NEARBY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MDLS COMING IN A BIT FASTER WITH ONSET OF PCPN LATER TDY AS SFC
LOW ORGANIZES ALONG GA/SC COAST. HOWEVER VERY DRY LLVLS WILL BE
BATTLING MOISTURE ADVECTION FROM S. AS SUCH DID NOT GO AS FAST AS
MDLS SUGGEST ONCE INTO S WV PLATEAU. LATEST RAP MDL SEEMS TO HAVE
A BETTER REFLECTION OF CURRENT THINKING AND USED IT AS A GUIDE
THRU 00Z. DO BRING IN HIGH POPS ACROSS SW VA BY 18Z AND THEN
SLOWLY SPREAD N UP THE EASTERN SLOPES TO INCLUDE MUCH OF
POCAHONTAS CO WITH THE CATEGORICAL POPS. HAVE A SHARP GRADIENT
HEADING W...WITH CHC POPS EXTENDING TO CRW- HTS AREA AND UP TOWARD
CKB. FEEL SE OH AND NW LOWLAND CO STAY DRY. HAVE ARND A THIRD OF
AN INCH QPF FOR SW VA AND UP THE EASTERN SLOPES. QUICKLY TAILS OF
W OF I79 CORRIDOR. EXIT BULK OF PCPN BY 06Z TO THE E...WITH
LINGERING CHC POPS FOR S/W TROF AXIS SLIDING THRU.
THERE IS SOME CONCERN FOR WINTRY PCPN AT THE ONSET ACROSS RIDGES
IN POCAHONTAS CO. MDLS INDICATE GOOD WET BULBING ARND 00Z TO
REFLECT SOME WET SN OR MIX POTENTIAL BEFORE SWITCHING TO RA LATER
IN EVE. USED SFC AND MODEL ALOFT TOO TO REFLECT THIS IN WX GRIDS.
WILL KEEP ACCUMULATIONS OUT OF GRIDS FOR NOW THOUGH.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
STILL SOME DISAGREEMENT IN THE MODELS WITH TRACK AND TIMING OF
THE SURFACE LOW FOR THURSDAY NIGHT INTO FRIDAY. NAM HAS TRENDED
MUCH FATHER SOUTH...BUT HAS THE SURFACE LOW AROUND THE MOUTH OF
CHESAPEAKE BAY...WHILE GFS AND ECMWF SHOW AN ELONGATED LOW FROM
THE CHESAPEAKE DOWN TO SOUTH CAROLINA. WITH THE NAM TRENDING SOUTH
TIGHTENED THE GRADIENT IN POPS ACROSS OUR CWA...GOING DRY ALONG
AND NW OF THE OHIO RIVER WHILE KEEPING LIKELY IN SW VA AND THE
SOUTHERN COAL FIELDS AND SOUTHERN AND CENTRAL MOUNTAINS OF WV.
PRECIP IS ALSO FASTER EXITING OUR CWA...SO TRENDED THAT WAY WITH
POPS AS ANOTHER SURFACE HIGH MOVES IN FRIDAY NIGHT. ONLY SMALL
CHANGES MADE ON TEMPS THURSDAY NIGHT THROUGH FRIDAY NIGHT...BUT
DID INCREASE HIGHS SOME ON SATURDAY WITH PLENTY OF APRIL SUNSHINE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WAVY FRONT APPROACHES THIS WEEKEND AND THEN HANGS NEARBY THE
BALANCE OF THE PERIOD. RIDGING ADVERTISED FOR EARLY NEXT WEEK OVER
THE PAST FEW DAYS IS ALL BUT GONE...THE GFS STILL AMPLIFYING ONE BUT
ALONG THE E COAST TUE. THAT IS WHEN THE ECMWF IS MARKEDLY DIFFERENT
WITH THE NORTHERN STREAM OVER CANADA...USING EASTERN CANADIAN
TROUGHING TO SINK THE CONFLUENCE...AND FRONTAL ZONE...SWD. THIS
WOULD MAKE THE LATTER PORTION OF THE FCST MUCH WETTER AND COOLER
THAN CURRENTLY CODED. AS PER HPC...IT AND TELECONNECTIONS DEPENDENT
UPON SW CONUS TROUGH WILL PLAY A ROLE IN HOW FAR N THE FRONT IS OVER
THE EASTERN CONUS DAYS 6-7.
DRY WEATHER GIVES WAY TO INCREASING CHANCE FOR SHOWERS NW TO SE DAY
3 NT AND DAY 4 WITH INITIAL APPROACH OF FRONT AND INITIAL UPPER
LEVEL WAVE. KEEP CHANCE THROUGH THE BALANCE OF THE FCST...HIGHEST N
AND NW...LOWEST S AND SE...HAVE HAVE JUST SLIGHT CHANCE EARLY ON.
MORE OR LESS EQUAL CHANCE FOR PRECIPITATION THROUGHOUT THE AREA DAY
7. ALSO INTRODUCED SLIGHT CHANCE FOR THUNDER DURING THE AFTERNOONS
AND EARLY EVENINGS BEGINNING MON AS DEW POINTS INCREASE TO NEAR 50.
BLENDED IN ADJMEXBC FOR HIGHS EARLY ON AND THEN HPC DAYS 6 AND 7
HIGHS AND ALL LOWS. ADJMEXBC APPEARED TOO LOW ON LOWS GIVEN SW
FLOW...RISING DEW POINTS AND CLOUDS.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY TO 06Z FRIDAY...
LIGHT SURFACE WINDS BECOMING GUSTY AGAIN AFTER 15Z...PARTICULARLY
ACROSS THE HIGHER TERRAIN. A LOW PRESSURE SYSTEM WILL APPROACH
FROM THE SOUTH LATE TDY...ALLOWING RA TO OVERSPREAD SW VA BY 18Z
AND SLOWLY SPREADING N UP THE WV MTNS. THIS WILL CREATE GENERAL MVFR
CONDITIONS ACROSS SOUTHWEST VA 18Z...SOUTHERN WV BY 00Z... AND UP
WV MTNS BY 03Z. KEEP SOUTHEAST OHIO AND NORTHERN WV REMAINING
VFR IN MID DECK. KHTS AND KCRW TRICKY AS THEY WILL BE ON THE NW
FRINGE OF BEST LLVL MOISTURE AND PCPN. WILL KEEP THEM VFR WITH
THIS ISSUANCE BUT ALLOW CIGS TO LWR INTO LOW END VFR. KEPT SHRA
MENTION OUT OF THOSE LOCALES DUE TO LOW CHC AT THIS RANGE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: LOW PRESSURE SYSTEM MAY SPREAD MOISTURE AND
LOW CIGS FARTHER NORTH THAN CURRENTLY FORECAST TOWARDS THE END OF
THE TAF PERIOD.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 04/04/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z FRIDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.FIRE WEATHER...
RH VALUES WILL AGAIN DIP INTO TEENS AND 20S PERCENT WISE AS DWPTS
MIX DOWN INTO THE TEENS AND TEMPS CLIMB. MOISTURE ADV FROM S IN
AFTN SHOULD ALLOW RH TO RECOVER UP TO CENTRAL WV WITH RA ACROSS SW
VA. HOWEVER...ACROSS PORTIONS OF NE KY...SE OH AND N WV...THE DRY
AIR WILL PREVAIL TDY. SOME AFTN GUSTS ARND 15 KTS MAY ALSO BE
EXPECTED ACROSS N WV. WITH VERY DRY 10 HR FUELS IN PLACE...AN
ENHANCED FIRE DANGER THREAT MAY BE REALIZED TODAY. CONDITIONS
WILL BE MONITORED AND COORDINATED WITH THE APPROPRIATE STATE
FORESTRY PERSONNEL FOR THE POTENTIAL FOR ANY FIRE WEATHER
STATEMENTS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...30
SHORT TERM...MZ
LONG TERM...TRM
AVIATION...30
FIRE WEATHER...30
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
113 PM CDT THU APR 4 2013
.UPDATED FOR 18Z TAF DISCUSSION...
.UPDATE.../ISSUED 955 AM CDT THU APR 4 2013/
AN UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY LOCATED OVER THE
ARKLATEX REGION WILL TRACK EAST ACROSS NORTH CENTRAL MISSISSIPPI
TODAY. LOOKING AT THE LATEST HRRR MODEL...BEST RAIN CHANCES WILL
OCCUR FROM EASTERN ARKANSAS TO NORTHWEST TENNESSEE. HAVE ADJUSTED
POPS ACCORDINGLY. HAVE ALSO LOWERED HIGHS SLIGHTLY. EXPECT
TEMPERATURES TO REMAIN IN THE UPPER 40S FOR HIGHS FOR THE MOST
PART DUE TO THE CLOUDS AND RAIN. UPDATE WILL BE OUT SHORTLY.
KRM
DISCUSSION... /ISSUED 308 AM CDT THU APR 4 2013/
SKIES WERE CLOUDY ACROSS THE MIDSOUTH WITH A FEW AREAS OF LIGHT
RAIN ON RADAR. WINDS WERE NORTHEAST AROUND 5 MPH WITH TEMPERATURES
HOLDING IN THE MID AND UPPER 40S. ON SATELLITE AN UPPER LEVEL LOW
WAS CENTERED IN SOUTHWEST OKLAHOMA WITH LEADING EDGE OF ASSOCIATED
ENHANCED CLOUD COVER AND PRECIPITATION ENTERING WESTERN ARKANSAS.
FOR TODAY AND TONIGHT...ONE LAST DREARY DAY FOR THE MIDSOUTH IN
REGARDS TO RAIN AND UNSEASONABLY COLD TEMPERATURES. FORTUNATELY
THE MODELS SHOW THE AFOREMENTIONED LOW BECOMING AN OPEN WAVE...AND
BEGINNING TO FILL AS IT PASSES JUST TO OUR SOUTH THIS
EVENING. THUS...RAINFALL AMOUNTS WILL LIKELY REMAIN UNDER A
QUARTER OF AN INCH FOR MANY MIDSOUTHERNERS. TEMPERATURES WILL
STRUGGLE TO REACH 50F ACROSS THE NORTH AND MID 50S SOUTH. AS THE
LOW TRACKS INTO ALABAMA AND GEORGIA TONIGHT AN UPPER LEVEL RIDGE
OVER THE PLAINS WILL QUICKLY BUILD INTO THE AREA. THIS SHOULD IN TURN
ALLOW FOR FASTER CLEARING EARLY FRIDAY MORNING. WITH DRIER AIR
WILL PUSHING IN FROM MISSOURI TEMPERATURES WILL EASILY CLIMB INTO
THE MID 60S.
THE REAL START TO THE MIDSOUTH WARMING TREND HOWEVER WILL BEGIN ON
SATURDAY AS LOW LEVEL WINDS TURN SOUTHERLY. SKIES THOUGH...MAY
BECOME PARTLY SUNNY THROUGHOUT THE DAY AS MODEL CROSS SECTIONS
YIELD THICKENING CIRRUS CLOUDS EXTENDING WELL EAST OF THE ROCKIES.
TEMPERATURES SHOULD STILL MANAGE TO MAKE IT INTO THE LOW AND MID 70S.
GULF MOISTURE WILL BEGIN TO SURGE NORTHWARD SATURDAY NIGHT AND SUNDAY
AS A COLD FRONT BECOMES STALLED ACROSS THE CORN BELT AND CENTRAL
PLAINS. WAA WILL CONTINUE ON SUNDAY DEVELOPING A DEEP LAYER CAP
BETWEEN 850 AND 700MB. THUS ANY ISOLATED CONVECTION FORMING WEST
OF THE MISSISSIPPI RIVER WILL EITHER WAA SHOWERS OR ELEVATED THUNDER.
HIGHS ON SUNDAY WILL REMAIN IN THE 70S WITH MILDER LOWS IN THE
MID AND UPPER 50S.
MONDAY THROUGH WEDNESDAY NIGHT...THIS PERIOD WILL SEE AN INCREASE
THREAT FOR STORMS AND SEVERE WEATHER AS A NEW STORM DEEPENS OVER
THE CENTRAL ROCKIES. THE UPPER FLOW OVER THE MIDSOUTH WILL BACK
FROM THE SOUTHWEST WITH SPEEDS INCREASING. THE COMBINATION OF
MINOR WAVES IN THE FLOW RIDING OVER THE STALLED BOUNDARY TO OUR
NORTH AND DEWPOINTS INCREASING TO THE MID AND UPPER 60S...WILL
WEAKEN THE ESTABLISHED CAP ALLOWING FOR SFC BASED CONVECTION. THE
GFS AND EURO BOTH SPORT 1500+ J/KG OF CAPE...7.0C+ LAPSE
RATES...AND LIFTED INDICES OF NEAR -6C. THE GFS ALSO IS INDICATING
0-1KM HELICITY VALUES IN EXCESS OF 3.0 M^2/S^2 INDICATING ROTATING
STORMS. SINCE MODEL RUNS OVER THE PAST THREE DAYS HAVE BEEN
CONSISTENT IN THE THREAT FOR SEVERE WEATHER FOR TUESDAY...WILL
INTRODUCE THIS THREAT IN THE UPCOMING HWO.
DEPENDENT ON AMOUNT OF CUMULUS CLOUD COVER/CONVECTION...DAYTIME
HIGHS COULD WARM CLOSE TO 80F. SOUTH WINDS WILL ALSO INCREASE AND
GUST TO 30MPH ON TUESDAY AS A SURFACE WAVE DEEPENS IN WEST TEXAS.
THIS FEATURE IS PROGGED TO MOVE INTO THE OZARKS ON WEDNESDAY AND
MAY PROVIDE A SECOND DAY THREAT FOR SEVERE WEATHER OVER OUR AREA.
JAB
&&
.AVIATION...
LOW CEILINGS IN RA/DZ/BR WILL CONTINUE TO PLAGUE THE MIDSOUTH
AIRPORTS THROUGH TONIGHT. GIVEN THE STUBBORN NATURE OF THIS UPPER
LOW AND PERSISTENT MOISTURE...HAVE OPTED TO KEEP LOW CEILINGS
THROUGH 06Z AT KMEM...WITH EARLIER CLEARING AT KJBR. AFTER 06Z THE
UPPER LOW WILL SHIFT EAST OF THE REGION...ALLOWING SKIES TO
GRADUALLY CLEAR THROUGH 12Z TOMORROW.
SAK
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 48 42 66 49 / 80 40 0 0
MKL 48 39 65 43 / 80 50 0 0
JBR 49 39 66 44 / 80 30 0 0
TUP 49 43 65 43 / 60 50 10 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
955 AM CDT THU APR 4 2013
.UPDATE...
AN UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY LOCATED OVER THE
ARKLATEX REGION WILL TRACK EAST ACROSS NORTH CENTRAL MISSISSIPPI
TODAY. LOOKING AT THE LATEST HRRR MODEL...BEST RAIN CHANCES WILL
OCCUR FROM EASTERN ARKANSAS TO NORTHWEST TENNESSEE. HAVE ADJUSTED
POPS ACCORDINGLY. HAVE ALSO LOWERED HIGHS SLIGHTLY. EXPECT
TEMPERATURES TO REMAIN IN THE UPPER 40S FOR HIGHS FOR THE MOST
PART DUE TO THE CLOUDS AND RAIN. UPDATE WILL BE OUT SHORTLY.
KRM
&&
.DISCUSSION... /ISSUED 308 AM CDT THU APR 4 2013/
SKIES WERE CLOUDY ACROSS THE MIDSOUTH WITH A FEW AREAS OF LIGHT
RAIN ON RADAR. WINDS WERE NORTHEAST AROUND 5 MPH WITH TEMPERATURES
HOLDING IN THE MID AND UPPER 40S. ON SATELLITE AN UPPER LEVEL LOW
WAS CENTERED IN SOUTHWEST OKLAHOMA WITH LEADING EDGE OF ASSOCIATED
ENHANCED CLOUD COVER AND PRECIPITATION ENTERING WESTERN ARKANSAS.
FOR TODAY AND TONIGHT...ONE LAST DREARY DAY FOR THE MIDSOUTH IN
REGARDS TO RAIN AND UNSEASONABLY COLD TEMPERATURES. FORTUNATELY
THE MODELS SHOW THE AFOREMENTIONED LOW BECOMING AN OPEN WAVE...AND
BEGINNING TO FILL AS IT PASSES JUST TO OUR SOUTH THIS
EVENING. THUS...RAINFALL AMOUNTS WILL LIKELY REMAIN UNDER A
QUARTER OF AN INCH FOR MANY MIDSOUTHERNERS. TEMPERATURES WILL
STRUGGLE TO REACH 50F ACROSS THE NORTH AND MID 50S SOUTH. AS THE
LOW TRACKS INTO ALABAMA AND GEORGIA TONIGHT AN UPPER LEVEL RIDGE
OVER THE PLAINS WILL QUICKLY BUILD INTO THE AREA. THIS SHOULD IN TURN
ALLOW FOR FASTER CLEARING EARLY FRIDAY MORNING. WITH DRIER AIR
WILL PUSHING IN FROM MISSOURI TEMPERATURES WILL EASILY CLIMB INTO
THE MID 60S.
THE REAL START TO THE MIDSOUTH WARMING TREND HOWEVER WILL BEGIN ON
SATURDAY AS LOW LEVEL WINDS TURN SOUTHERLY. SKIES THOUGH...MAY
BECOME PARTLY SUNNY THROUGHOUT THE DAY AS MODEL CROSS SECTIONS
YIELD THICKENING CIRRUS CLOUDS EXTENDING WELL EAST OF THE ROCKIES.
TEMPERATURES SHOULD STILL MANAGE TO MAKE IT INTO THE LOW AND MID 70S.
GULF MOISTURE WILL BEGIN TO SURGE NORTHWARD SATURDAY NIGHT AND SUNDAY
AS A COLD FRONT BECOMES STALLED ACROSS THE CORN BELT AND CENTRAL
PLAINS. WAA WILL CONTINUE ON SUNDAY DEVELOPING A DEEP LAYER CAP
BETWEEN 850 AND 700MB. THUS ANY ISOLATED CONVECTION FORMING WEST
OF THE MISSISSIPPI RIVER WILL EITHER WAA SHOWERS OR ELEVATED THUNDER.
HIGHS ON SUNDAY WILL REMAIN IN THE 70S WITH MILDER LOWS IN THE
MID AND UPPER 50S.
MONDAY THROUGH WEDNESDAY NIGHT...THIS PERIOD WILL SEE AN INCREASE
THREAT FOR STORMS AND SEVERE WEATHER AS A NEW STORM DEEPENS OVER
THE CENTRAL ROCKIES. THE UPPER FLOW OVER THE MIDSOUTH WILL BACK
FROM THE SOUTHWEST WITH SPEEDS INCREASING. THE COMBINATION OF
MINOR WAVES IN THE FLOW RIDING OVER THE STALLED BOUNDARY TO OUR
NORTH AND DEWPOINTS INCREASING TO THE MID AND UPPER 60S...WILL
WEAKEN THE ESTABLISHED CAP ALLOWING FOR SFC BASED CONVECTION. THE
GFS AND EURO BOTH SPORT 1500+ J/KG OF CAPE...7.0C+ LAPSE
RATES...AND LIFTED INDICES OF NEAR -6C. THE GFS ALSO IS INDICATING
0-1KM HELICITY VALUES IN EXCESS OF 3.0 M^2/S^2 INDICATING ROTATING
STORMS. SINCE MODEL RUNS OVER THE PAST THREE DAYS HAVE BEEN
CONSISTENT IN THE THREAT FOR SEVERE WEATHER FOR TUESDAY...WILL
INTRODUCE THIS THREAT IN THE UPCOMING HWO.
DEPENDENT ON AMOUNT OF CUMULUS CLOUD COVER/CONVECTION...DAYTIME
HIGHS COULD WARM CLOSE TO 80F. SOUTH WINDS WILL ALSO INCREASE AND
GUST TO 30MPH ON TUESDAY AS A SURFACE WAVE DEEPENS IN WEST TEXAS.
THIS FEATURE IS PROGGED TO MOVE INTO THE OZARKS ON WEDNESDAY AND
MAY PROVIDE A SECOND DAY THREAT FOR SEVERE WEATHER OVER OUR AREA.
JAB
&&
.AVIATION...
12Z TAF CYCLE (04/12Z-05/12Z)
SURFACE LOW PRESSURE WILL MOVE ALONG THE NORTHEASTERN GULF COAST
WHILE AN UPPER LEVEL TROUGH MOVES OVER THE MIDSOUTH TODAY. THIS WILL
CAUSE RAIN ACROSS THE MIDSOUTH. FOR TODAY...THINK IFR CONDITIONS
WILL PREDOMINATE AT KMEM...KMKL...AND KTUP WITH MVFR CONDITIONS AT
KJBR. CONDITIONS THIS EVENING GRADUALLY IMPROVING TO VFR AT
KMEM...KMKL...AND KJBR AS THE LOW PRESSURE SYSTEM MOVES EASTWARD
AND THE RAIN ENDS. KTUP IS EXPECTED TO IMPROVE TO MVFR AROUND
05/06Z.
WINDS TODAY NE 7-10 KTS. WINDS TONIGHT NORTHERLY 3-8 KTS.
JCL
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 48 42 66 49 / 80 40 0 0
MKL 48 39 65 43 / 80 50 0 0
JBR 49 39 66 44 / 80 30 0 0
TUP 49 43 65 43 / 60 50 10 0
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
505 AM EDT THU APR 4 2013
.SYNOPSIS...
LOW PRESSURE WAS OVER THE NORTHERN GULF OF MEXICO THIS MORNING
WITH HIGH PRESSURE OVER THE MID ATLANTIC REGION. THE LOW WILL MOVE
ACROSS GEORGIA AND FLORIDA TODAY THEN OFF THE CAROLINA COAST BY
FRIDAY MORNING. HIGH PRESSURE WILL COVER THE REGION BEHIND THIS
SYSTEM FOR SATURDAY AND SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EDT THURSDAY...
STARTING WITH SURFACE DEW POINTS IN THE SINGLE DIGITS AND TEENS
AND A LOT OF ROOM TO COOL DOWN TO THE WET BULB AS MOISTURE
INCREASES FROM THE TOP DOWN. LATEST RUNS OF THE RAP AND LOCAL WRF
SUGGEST SLOW PROGRESS OF THE LEADING EDGE OF THE PRECIPITATION
INTO THE DRY AIR. HAVE SLOWED DOWN THE ARRIVAL TIME IN THE
NORTHERN COUNTY WARNING AREA TODAY.
FOR PRECIPITATION TYPE...BUFKIT FORECAST SOUNDINGS ALONG THE
SOUTHERN BLUE RIDGE SHOW SNOW AND SLEET FOR MUCH OF THE DAY. HAVE
ISSUED A WINTER WEATHER ADVISORY FOR WATAUGA COUNTY...EXPECTING
THE HIGHEST SNOW AND SLEET AMOUNTS ALONG THE AVERY COUNTY LINE.
BEECH MOUNTAIN MAY HAVE 3 INCHES OF NEW SNOW/SLEET TODAY.
AS PRECIPITATION MOVES INTO THE FORECAST AREA THIS
MORNING...IN-SITU WEDGE FORMS. ALREADY STARTING OUT CLOUDY AND
WITH PRECIPITATION TEMPERATURES WILL REMAIN BELOW NORMAL. USED A
NON DIURNAL TREND FOR HOURLY TEMPERATURES.
BEST ISENTROPIC LIFT AND UPPER DIFFLUENCE CROSS THROUGH THE AREA
AREA BETWEEN 18Z/2PM AND 06Z/2AM. PROBABILITY OF PRECIPITATION
BEGINS TO LOWER IN THE MOUNTAINS AS THE LOW COMING ACROSS THE GULF
COAST STATES MOVES OFFSHORE AND WINDS COME AROUND TO THE
NORTHWEST.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 400 AM EDT THURSDAY...
BY SUNRISE FRIDAY...THE GFS AND ECMWF FORECAST MODELS ARE IN DECENT
AGREEMENT THAT THE LOW PRESSURE SYSTEM WHICH BROUGHT RAIN TO OUR
AREA EARLIER IN THE NIGHT WILL BE MOVING RAPIDLY UP THE NORTH
CAROLINA COAST. AS THE LOW CONTINUES NORTHEAST...WINDS ACROSS OUR
AREA WILL BECOME INCREASINGLY NORTHWESTERLY...DRAWING DRIER AIR IN
FROM THE GREAT LAKES. AS SUCH...SHOWER ACTIVITY WILL TAPER OFF
THROUGH THE MORNING...AND EXPECT TO SEE CLOUD COVER BREAK UP FROM
WEST TO EAST DURING THE AFTERNOON.
A RIDGE OF HIGH PRESSURE WILL PASS ACROSS THE APPALACHIAN CHAIN
FRIDAY NIGHT...AND WILL MOVE OFF OF THE ATLANTIC COAST SATURDAY
AFTERNOON. DESPITE ABUNDANT AFTERNOON SUNSHINE...EASTERLY WINDS
FLOWING AROUND THE DEPARTING HIGH PRESSURE RIDGE WILL CARRY COOLER
AIR FROM THE ATLANTIC INTO OUR AREA. THEREFORE...UNDERCUT GUIDANCE
BY A FEW DEGREES FOR SATURDAY AFTERNOON TEMPERATURES...LIMITING
HIGHS TO THE UPPER 50S AND THE LOW 60S FOR MOST OF THE AREA.
BY SUNDAY...AN UPPER LEVEL TROUGH BEGINS TO SET IN ACROSS THE
WESTERN HALF OF THE UNITED STATES...ALLOWING UPPER LEVEL RIDGING
ACROSS THE EASTERN HALF TO BECOME INCREASINGLY AMPLIFIED. AS
SUCH...SUNDAY AFTERNOON TEMPERATURES WILL BE AMONG THE WARMEST
EXPERIENCED THIS YEAR...WITH HIGHS REACHING TO NEAR 70 ACROSS THE
PIEDMONTS...AND INTO THE MID/UPPER 60S ACROSS THE MOUNTAINS. A COLD
FRONT WILL SINK FROM THE GREAT LAKES AS FAR SOUTH AS THE OHIO RIVER
VALLEY DURING THE AFTERNOON...HOWEVER ANOTHER DEVELOPING LOW
PRESSURE SYSTEM ACROSS THE PLAINS WILL CAUSE THE FRONT TO STALL
BEFORE REACHING INTO OUR AREA.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 400 AM EDT THURSDAY...
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY BUILDING 500MB
HEIGHTS...INCREASING MOISTURE...AND WARMER TEMPERATURES AS A WESTERN
U.S. TROF CONTINUES TO DEEPEN.
UPPER LEVEL HEIGHTS WILL REALLY BEGIN TO RISE MONDAY AS THE WESTERN
TROF DEEPENS. THE 00Z ECMWF APPEARS TOO FAR EAST WITH THIS
SYSTEM...AND LEANED TOWARD THE CANADIAN/GFS MODELS KEEPING A
SOUTHWEST FLOW OVER OUR AREA RESULTING IN OUR FIRST TASTE OF ABOVE
NORMAL TEMPERATURES IN WEEKS. MEANWHILE...AT THE SFC...
SOUTH/SOUTHWEST WINDS USHER IN HIGHER DEWPOINTS...DEEPER MOISTURE
WITH PWATS 1-2 STANDARD DEVIATIONS ABOVE NORMAL...TUESDAY AND
WEDNESDAY. WEAK UPPER LEVEL WAVES IN ADVANCE OF THE DEEPENING TROF
INTERACTING WITH THIS INCREASING MOISTURE WILL BRING A SLIGHT CHANCE
OF SHOWERS TUESDAY AND WEDNESDAY. THE 12Z GFS SUGGESTS A DRIER DAY
TUESDAY WITH A MORE AMPLIFIED PATTERN COMPARED TO PREVIOUS MODEL
RUNS...KEEPING THE BEST UPPER LEVEL SUPPORT/LOW LEVEL CONVERGENCE
WELL WEST OF OUR AREA.
A DEEP SOUTHWEST FLOW WILL KEEP ABOVE NORMAL TEMPS...MOSTLY CLOUDY
SKIES AND A RISK OF SHOWERS/ISOLATED STORMS ON WEDNESDAY.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AS OF 140 AM EDT THURSDAY...
CEILINGS WILL LOWER OVER VIRGINIA AND THE CAROLINAS AS DEEPER
MOISTURE MOVES NORTHEAST OUT OF THE TENNESSEE VALLEY. RAIN ARRIVES
AFTER 18Z/2PM WITH MVFR CEILINGS BY 00Z/8PM. MEDIUM CONFIDENCE ON
THE TIMING OF THE RAIN AND MVFR CONDITIONS.
RAIN AND MVFR TO IFR CEILINGS AND VISIBILITIES ARE EXPECTED
OVERNIGHT. EASTERLY SURFACE AND LOW LEVEL WINDS WILL LIKELY BRING
IFR CONDITIONS TO ROA/LYH AND DAN AFTER 06Z.
BY FRIDAY THE STORM SYSTEM WILL BE OFF THE EAST COAST. LOW LEVEL
MOISTURE WILL REMAIN OVER THE MOUNTAINS...RESULTING IN PROLONGED
MVFR CEILINGS AT LWB/BLF. CONDITIONS WILL BE GRADUALLY IMPROVING
EAST OF THE BLUE RIDGE BY LATE FRIDAY.
HIGH PRESSURE WILL THEN BUILD IN FOR SATURDAY...BRINGING DRY
WEATHER AND RETURNING ALL TAF LOCATIONS TO VFR THROUGH MONDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NCZ018.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...NF/PH
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CDT FRI APR 5 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 311 PM CDT FRI APR 5 2013
WATER VAPOR IMAGERY THIS AFTERNOON SHOWING A MID-LEVEL SHORTWAVE
TROUGH MOVING THROUGH THE INTERMOUNTAIN WEST. AT THE SURFACE...
CYCLOGENESIS WAS TAKING PLACE EAST OF THE WY ROCKIES WITH A WARM
FRONT EXTENDING THROUGH NEBRASKA. LIFT AHEAD OF THE LOW AND OVER THE
WARM FRONT WAS PRODUCING INCREASING MID-LEVEL CLOUD WITH RADAR
MOSAIC/SURFACE OBSERVATIONS INDICATING SPORADIC -SN REACHING THE
GROUND FROM WEST CENTRAL-SOUTH CENTRAL MN. OTHERWISE...HIGH/MID
CLOUDS WERE INCREASING/THICKENING FROM WEST TO EAST ACROSS THE
FORECAST AREA WITH TEMPERATURES RANGING FROM THE UPPER 30S ACROSS
NORTH CENTRAL WI TO 50 ACROSS PORTIONS OF NORTHEAST IA/FAR SOUTHWEST
WI.
FOR TONIGHT...SURFACE LOW WILL CONTINUE TO DEVELOP AND MOVE OUT OF
THE PLAINS INTO SOUTHERN MN BY 12Z WITH INCREASING 850-700MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW FOCUSING INTO
AREAS NORTHEAST OF I-94. AS A RESULT...CONFIDENT ENOUGH TO CARRY
LIKELY TO CATEGORICAL POPS ACROSS THAT AREA...TAPERING OFF TO
CHANCES SOUTHWEST OF I-94. AS FAR AS PRECIPITATION TYPES...RAP
SOUNDINGS NORTHEAST OF I-94 SHOW EVAPORATIVE COOLING AS THE COLUMN
SATURATES...WITH BOUNDARY LAYER STILL WARM ENOUGH TO SUPPORT RAIN.
THE NAM ON THE OTHERHAND COOLS THE ENTIRE COLUMN BELOW 0C FOR ALL
SNOW WHICH SEEMS A BIT AGGRESSIVE. BOTTOM LINE...LOOKS LIKE A
RAIN/SNOW MIX MOVING IN MAINLY ALONG AND NORTH OF I-94 THIS EVENING.
LOOKS LIKE MAIN SNOW AREA WILL BE NORTH OF THE AREA...BUT TAYLOR
COUNTY COULD BE COLD ENOUGH TO SEE ACCUMULATIONS OF 1/2 TO PERHAPS
AS MUCH AS 2 INCHES ACROSS FAR NORTHERN PORTION OF THE COUNTY. AS
WARMER AIR ALOFT MOVES INTO THE AREA AFTER MIDNIGHT...LOOK FOR THE
SNOW TO BECOME MORE OF A RAIN/SLEET MIX...POSSIBLY ALL RAIN TOWARD
MORNING.
MODELS CONTINUE TO SHOW THE LOW MOVING EAST THROUGH CENTRAL WI ON
SATURDAY WITH AREAS ALONG AND SOUTH OF I-90 IN THE WARM SECTOR. RAIN
EXPECTED TO CONTINUE ALONG AND NORTH OF THE LOW. MEANWHILE...THE NAM
DEVELOPS SOME 0-3KM MUCAPE LATE MORNING/AFTERNOON IN THE WARM SECTOR
OF AROUND 400J/KG. THIS WILL BE AHEAD OF FAIRLY STRONG 925-700MB
FRONTOGENESIS ASSOCIATED WITH THE COLD FRONT OF THE LOW. BUFKIT
SHOWING THAT THIS IS LONG/SKINNY CAPE WHICH WILL LIKELY SUSTAIN A
FEW THUNDERSTORMS. BASED ON THIS SIGNAL...WILL CONTINUE THE THREAT
FOR A FEW STORMS IN THE FORECAST MAINLY ALONG/SOUTH OF I-90.
OTHERWISE...LOOK FOR TEMPERATURES TO CLIMB INTO THE 55-60 DEGREE
RANGE SOUTH OF THE WARM FRONT...AND IN THE 40S TO NEAR 50 ALONG AND
NORTH OF I-94. RAIN AND WARMTH FOR SNOWMELT MAY LEAD TO SOME HYDRO
ISSUES. DETAILS OF THIS IS COVERED IN THE HYDROLOGY SECTION BELOW.
THE LOW PULLS EAST INTO THE GREAT LAKES REGION SATURDAY NIGHT WITH
LINGERING RAIN CHANCES CONFINED TO THE EVENING HOURS ALONG AND EAST
OF THE MISSISSIPPI RIVER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 311 PM CDT FRI APR 5 2013
SUNDAY EXPECTED TO BE DRY AS A RIDGE OF HIGH PRESSURE DRIFTS ACROSS
THE REGION. LOOK FOR IN THE MIDDLE 40S TO MIDDLE 50S.
FOR SUNDAY NIGHT INTO MONDAY...A DEEPENING UPPER LEVEL TROUGH OF LOW
PRESSURE OVER THE WESTERN STATES WILL PRODUCE INCREASING SOUTHWEST
FLOW ALOFT INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION.
CYCLOGENESIS AND BROAD MOISTURE TRANSPORT ACROSS THE PLAINS INTO OUR
AREA WILL PRODUCE A CHANCE OF A RAIN OR RAIN/SNOW MIX SUNDAY NIGHT
AND ALL RAIN ON MONDAY. PLAN ON LOWS SUNDAY NIGHT IN THE 30S TO NEAR
40 WITH HIGHS ON MONDAY IN THE UPPER 40S TO THE MIDDLE 50S.
MEDIUM RANGE MODELS SHOWING A RATHER ACTIVE WEATHER PATTERN FOR THE
REST OF THE WORK WEEK. HOWEVER...THEY OFFER DIFFERING SOLUTIONS WITH
REGARD TO THE EVOLUTION OF THE WESTERN TROUGH AND SURFACE
CYCLOGENESIS AND IMPACT ON THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THE GFS AND GEM SHOWING SOME SIMILARITY IN EJECTING THE
TROUGH/SURFACE LOW TOWARD THE AREA MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH MORE PHASING WITH THE NORTHERN STREAM FLOW. THIS KEEPS US
IN AN OVERALL WARMER/RAIN SCENARIO. THE ECMWF ON THE OTHER HAND
WANTS TO KEEP THE FLOW SPLIT THROUGH TUESDAY WHICH KEEPS THE LOW
OVER THE PLAINS THUS KEEPING AREAS MAINLY NORTH OF I-90 DRY WITH
UPSTREAM RIDGING. THE ECMWF THEN TAKES THE MAIN SURFACE LOW TRACK
FARTHER SOUTH INTO THE OHIO RIVER VALLEY REGION WITH AN INVERTED
TROUGH OVER US. THIS MAY LEAD TO A COLDER RAIN OR RAIN SNOW MIX.
WILL GO WITH A MODEL CONSENSUS FOR NOW AND HOPE FOR BETTER
RESOLUTION WITH LATER RUNS. CONSENSUS YIELDS A CHANCE OF RAIN FROM
MONDAY NIGHT STRAIGHT THROUGH FRIDAY. TEMPERATURES THROUGH THE
PERIOD LOOK TO BE COLDER THAN NORMAL WITH GENERAL TROUGHINESS AND
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 311 PM CDT FRI APR 5 2013
RIVER STATUS...
ICE JAM ISSUES NOW BEING REPORTED ON THE BLACK ON THE NORTH SIDE OF
NEILLSVILLE WITH THAWING. HYDROGRAPHS ACROSS THE REST OF AREA SHOW
TRIBUTARY RIVERS AND STREAMS INTO THE MISSISSIPPI RUNNING WITHIN
BANK BUT HIGHER THAN NORMAL GIVEN THE SNOW MELT. MOST OF THE HIGHER
RIVER FLOWS ARE CONFINED TO RIVERS NORTH OF I-90 WHERE SNOW PACK
STILL EXISTS. BESIDES THE BLACK RIVER...THE TREMPEALEAU IS ALSO A
CONCERN AT THE MOMENT.
SNOW PACK...
LATEST NOHRSC DATA SHOWED SNOW WATER EQUIVALENTS STILL IN THE 1-3
INCH RANGE OVER WINONA...BUFFALO...TREMPEALEAU AND JACKSON
COUNTIES...WHILE 2-4 INCH AMOUNTS WERE PRESENT IN CLARK AND TAYLOR
COUNTIES.
RAINFALL...
THE SYSTEM COMING IN FOR TONIGHT AND SATURDAY IS EXPECTED TO PRODUCE
1/4 OF AN INCH OR LESS SOUTHWEST OF I-94 AND AROUND 1/2 INCH
RAINFALL/LIQUID EQUIVALENT FROM ANY SNOW NORTH OF HIGHWAY 10 IN
WISCONSIN. ADDITIONAL RAINFALL IS POSSIBLE SUNDAY NIGHT WITH THE
POTENTIAL FOR MORE MODERATE RAINFALL MONDAY THROUGH WEDNESDAY OF
NEXT WEEK.
TEMPERATURES...
TEMPERATURES IN THE MIDDLE 30S TO MIDDLE/UPPER 40S TODAY CONTINUES
TO PRODUCE SNOWMELT. TEMPERATURES MAY NOT FALL BELOW FREEZING
TONIGHT ALONG WITH WARMER CONDITIONS ANTICIPATED ON SATURDAY. THIS
WILL CAUSE ADDITIONAL SNOW MELT. MOST OF THE NEXT 7 DAYS LOOK TO
HAVE DAYTIME TEMPERATURES AT LEAST 40 FOR CONTINUED FAVORABLE SNOW
MELT CONDITIONS.
FROST DEPTH...
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 WILL LIKELY CAUSE ADDITIONAL RUNOFF OF
SNOW MELT AND FALLEN PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
DUE TO LESS RAINFALL EXPECTED FOR TONIGHT THROUGH SATURDAY...MAIN
FLOODING CONCERN WOULD COME MOSTLY FROM SNOW MELT THE NEXT FEW DAYS.
RIVERS AND STREAMS FROM WINONA AND WABASHA COUNTIES INTO BUFFALO
TREMPEALEAU...JACKSON...CLARK AND TAYLOR CONTINUE BE FOCUS OF
CONCERN. WILL KEEP THE ESF GOING BASED ON THE LISTED FACTORS ABOVE.
POTENTIAL IS THERE FOR A FLOOD WATCH...BUT WILL CONTINUE ESF AND
CONTINUE ASSESSING THE SITUATION AT HAND WITH SNOWMELT AND FALLEN
PRECIPITATION. WILL ALSO CONTINUE TO KEEP A VIGILANT EYE ON ON THE
SITUATION FOR MODERATE RAINFALL POTENTIAL MONDAY THROUGH WEDNESDAY
OF NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
HYDROLOGY....DAS
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 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
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
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 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 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 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 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...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 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 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