Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/02/20
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
621 PM CDT Fri May 1 2020
.UPDATE...
Issued at 620 PM CDT Fri May 1 2020
Forecast is on track this evening. No major changes are planned.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 247 PM CDT Fri May 1 2020
Forecast challenges revolve around fire weather concerns on Saturday.
Currently, breezy to windy northwest winds have overtaken pretty
much the entire CWA now, behind a cold front that has passed over
into MN. Under a mostly sunny sky, temperatures have warmed into the
70s and 80s everywhere except portions of north central South Dakota
where the cold front had moved through earlier this morning. There,
temperatures have only been able to muster 60s to around 70 degrees
for many locations. There`s also been more low level/boundary layer
moisture around today, so that has helped to offset the warmer
temperatures, keeping afternoon relative humidities generally
between 30 and 55 percent.
Between now and late Saturday night, the only place currently
holding any precipitation potential is the far southwestern forecast
zones later tonight into Saturday morning, where a little bit of
light showery potential will exist when the next area of low
pressure lifts out across the central plains.
Mainly, the concern heading into Saturday is how dry the airmass
will be that advects into the CWA tonight into Saturday behind the
cold front that has moved through the forecast area today. RAP model
boundary layer RH/mixing tool rh values suggest a good portion of
the CWA could be dealing with RH values Saturday afternoon less than
30 percent (some areas close to 20 percent). BUFKIT suggests there
could be some gusts of 20 to 25 mph Saturday afternoon, mainly
along/north of a line from Britton to Clear Lake. Coordination
resulted in a Fire Weather Watch for Big Stone and Traverse Counties
in Minnesota for Saturday afternoon. Overall, Red Flag conditions at
this point do not appear to be a slam dunk for any fire weather
zones on Saturday. But, if conditions like that could materialize,
the highest confidence/greatest potential for it right now is across
the far northeast tip of South Dakota over into west central MN.
Temperatures over the next 36 to 48 hours will remain, generally,
near to above normal. But, the cooling trend will become more
noticeable by late Saturday night heading into the second half of the
weekend, due to a "back-door" cold front progged to push south and
east into the CWA Saturday evening/night. Shallow cold airmass temps
from the surface to 925hpa suggests temperature recovery into the
70s may be tough to come by for a few days after Saturday.
.LONG TERM...(Sunday through Friday)
Issued at 247 PM CDT Fri May 1 2020
The pattern starts with a ridge overhead Sunday, with high pressure
centered in Canada with a surface ridge extending down along the Red
River Valley, and low pressure in Montana. Dry initially,
southerly flow becomes more pronounced into the evening, with a
plume of "moisture" moving up into the Dakotas. Dewpoints reach near
50 at the surface with NAM profiles suggesting this moisture is
mixed through the boundary layer by the time it arrives. MUCAPE will
peak between 500-1500 j/kg, with that maximum along a north south
front that moves across the CWA Monday. Environmental winds below
400mb are 30kts or less, which will limit the severe weather threat.
The GFS has a much stronger low compared to other deterministic
members at this point.
There is evidence for a wave following mid-week as an upper low
develops over eastern North America, but deterministic guidance is
somewhat divergent on handling these weak features.
As for temperatures, will stay continued seasonal with a partial
cool down early Sunday for the northeast CWA with a backdoor front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 620 PM CDT Fri May 1 2020
VFR conditions are expected through the period with breezy
northwest winds.
***Construction to improve the taxiway for runway 13 at the KPIR
terminal may cause an occasional temporary visibility reduction due
to blowing dust (bldu), mainly during daytime hours UFN.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...Fire Weather Watch from Saturday afternoon through Saturday
evening for MNZ039-046.
&&
$$
UPDATE...Wise
SHORT TERM...Dorn
LONG TERM...Connelly
AVIATION...Wise
Area Forecast Discussion
National Weather Service Bismarck ND
936 PM CDT Fri May 1 2020
.UPDATE...
Issued at 922 PM CDT Fri May 1 2020
Skies are clearing in broad subsidence as seen on the water vapor
loops this evening. Current surface features have high pressure
across Montana sliding southeast tonight. Winds are diminishing
as the surface becomes decoupled from the boundary layer winds.
Current forecast looks good for tonight.
Friday looks like a near critical fire weather day across central
and northwest North Dakota. New evening runs of the HRRR model
have dewpoints into the lower to middle 20s. However, the stronger
surface winds will be across the north central, not where the
lowest afternoon Relative Humidity is forecast, which is more
southwest. So agree in holding off on any fire weather watches or
warnings at this time for Saturday afternoon.
UPDATE Issued at 633 PM CDT Fri May 1 2020
Latest sounding data taken at 6 pm CDT shows a well mixed
atmosphere up through nearly 10k ft MSL at Bismarck. The Mid
level water vapor channel shows the strongest subsidence lies
across southwest North Dakota spreading northeast into south
central North Dakota.
The main feature in the short term will continue to be gusty
winds to 30 mph for a short period early this evening. By mid
evening the winds will generally be less than 15 mph. Skies will
clear as the area of weak subsiding air spreads across the region
tonight. Current forecast looks ok.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 204 PM CDT Fri May 1 2020
Latest suite of satellite imagery shows a departing shortwave
trough sliding through southern Manitoba this afternoon with
weaker shortwaves trailing back into northeast Montana and western
North Dakota. Isolated scattered showers still possible through
this afternoon, but most areas will be dry and windy. Expect a
clearing sky tonight followed by a plethora of sunshine Saturday.
Lows tonight will be in the upper 30s west to mid 40s south
central. Highs Saturday will be in the upper 60s to lower 70s.
Northwest winds 15 to 25 mph along and east of the Missouri River
early in the afternoon will weaken through the afternoon.
.LONG TERM...(Saturday night through Friday)
Issued at 204 PM CDT Fri May 1 2020
A backdoor cold front grazes the James River Valley Saturday night
into early Sunday morning. Nothing significant with this feature.
Mid-upper level ridge will be moving overhead Saturday night into
Sunday morning, keeping conditions dry. However, a shortwave
trough in southwest flow aloft will impinge into western North
Dakota Sunday afternoon resulting in showers thunderstorms. The
GFS shows a narrow ribbon of most unstable cape around 1000 J/kg,
deep layer shear of 35kt- 40kt, and favorable lapse rates in the
far southwest Sunday afternoon. Will continue to monitor these
trends for any changes and possible severe threat during late
Sunday afternoon southwest. Otherwise, an area of primarily
showers migrate across western and central North Dakota Sunday
night into early Monday morning. A stronger upper low and
associated shortwave trough both advertised differently in the
GFS/ECMWF deterministic solutions. The ECMWF essentially is dry,
while the GFS advertises one to two inches of rainfall across
southern North Dakota. The GFSEnsembles are much lower, averaging
around a quarter of one inch. WPC qpf has backed off from eight
tenths over Bismarck now down to about a third of an inch. This is
more in line with the GFSEnsemebles but still higher than the
deterministic ECMWF. Much uncertainty continues on precipitation
amounts at this time.
Once this system departs, northwest upper flow will become dominate
with a couple of strong shortwaves and much cooler air for the rest
of the week. Temperatures will be below normal, as depicted on the
CIPS Analog. The first push of precipitation and cooler air arrives
Thursday. Another push is slated for the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 633 PM CDT Fri May 1 2020
VFR expected at all TAF locations. Surface high pressure across
Montana will move east tonight and Saturday. Initial gusty
northwest winds will diminish this evening.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
624 PM CDT Fri May 1 2020
.SHORT TERM...(This evening through Saturday)
Issued at 210 PM CDT Fri May 1 2020
A weak front...more like a winds shift is moving across the
forecast area today. As of 2pm it is through the Tri-cities and is
on its way southeast. Skies are clear and insolation is plentiful.
Mixing behind the front and plentiful insolation have helped temps
soar into the 80s for most locations by 2pm. Highs in the mid-
upper 80s looks to be on track...maybe a 90 degree may peek its
head in, but don`t expect it to be widespread at this time.
A very weak wave is expected to move across the High Plains and
with plentiful insolation some thunderstorms are expected to
develop across Colorado, Wyoming and the NE Panhandle. However, as
the sunsets, this weak disturbance will struggle to provide much
in the way downstream. Expect much of the activity to diminish
before it reaches the GID forecast area, but have kept a small
chance for areas to the west and north. Now the 12 NAM and NAMnest
disagree and do pull quite a bit of QPF over south central
Nebraska. But throughout the morning, the high-res HRRR runs, do
not support this happening. Overnight, the main area of concern
looks to remain north of the forecast area. Instability will be
greatest to the west...do not expect much for thunder, and no
strong to severe storms tonight. If you get rain...count yourself
among the lucky...most will likely remain dry.
Saturday will be cooler than today, as cloud cover will persist
across portions of the area. One question though...is if this
activity tonight remains as far to the north as it seems...will
the whole area be socked in. Think there could be breaks tomorrow,
which could help temperatures increase a bit beyond currently
forecasted. Winds will be north to northeasterly and breezier than
today. Highs ranging from the mid 60s to the upper 70s are
possible...and of course an increase of sunshine may increase
these.
.LONG TERM...(Saturday night through Friday)
Issued at 210 PM CDT Fri May 1 2020
An active pattern through the extended forecast.
The cold front that moved through today will continue to slide
southward through Kansas. This will keep the focus of the majority
of precipitation to our south. While model blends include pops for
the whole area Saturday night into Sunday....feel it`ll likely be
dry for most with the better chances across KS.
A disturbance will move across the Northern Plains and may
develop precip Sunday night into Monday and right now that looks
like the best shot in the first few days of the forecast.
Temps for the weekend look to be in the 70s for most of the
area...a pleasant spring weekend.
Another...stronger disturbance will in behind the first one Monday
morning and bring another decent chance for precipitation...there
are some discrepancies on timing of this wave, with the EC being
faster than the GFS/NAM. Behind this wave...mid-week surface high
pressure will build in. Yet another disturbance moves in for the
end of the work-week and will bring another chance for precip.
With discrepancies earlier in the week...won`t worry to much
about this period now.
Overall temps are expected in the 70s through the workweek with
lows in the 40s.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 616 PM CDT Fri May 1 2020
Anticipate VFR conditions through the forecast period. A mid
level disturbance to the west has triggered a few tstms that have
moved into the Neb panhandle and northeast CO. There is a slight
chance these could hold together and move into the terminal areas
after midnight but at the moment chances look to be twenty percent
or less so will leave out mention for now. Winds expected to
remain northerly overnight and could be on the gusty side Sat
morning.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...Billings Wright
LONG TERM...Billings Wright
AVIATION...Ewald
Area Forecast Discussion
National Weather Service New York NY
1149 PM EDT Fri May 1 2020
.SYNOPSIS...
A surface trough continues to shift east of the region tonight.
High pressure then builds in Saturday. A series of fronts then
cross the area Saturday night through Monday. High pressure
builds in for Tuesday, but weakens at night into Wednesday
morning as low pressure passes to the south. High pressure
rebuilds thereafter through Friday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Upper level trough and surface trough move east of the region
overnight. Along the trough axis, some upper level forcing as
evident from model forecast fields of mid level positive vorticity
advection. NAM12 and HRRR both still indicate some possible shower
development along part of the axis, mainly for Long Island and
Southern Connecticut. While trends earlier this evening
decreased with shower coverage, did not remove it from forecast
altogether with isolated to widely scattered rain showers, again
mainly for Long Island and Southern Connecticut.
Otherwise, made minor adjustments with hourly temperatures,
dewpoints, winds, as well as cloud coverage to better match
observed trends. Expecting some gusts to occur overnight up to
near 20-25 mph. Along with some broken cloud coverage heading
into the overnight, this will mitigate radiational cooling.
Winds shifts out of the northwest behind the trough and much
drier air works its way into the forecast area. Dew points fall
10 degrees overnight into the 40s. This coupled with clearing
skies will cause ambient temperatures to settle around 45-50
degrees prior to sunrise.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
With the trough well off to the east by Saturday morning mid level
heights begin to build and the resulting subsidence clears out skies
setting up a pleasant day. Model soundings have the 925 mb
temperature around 11-12C near 700-800m. Meaning once mixing begins
in the late morning and early afternoon, we could see temperatures
in the upper 60s and low 70s. This would be our first chance to
reach 70 degrees in over a month.
Conditions change towards the evening. Once the surface ridge axis
makes its way across southern New York, winds shift out of the
south allowing for moisture to return to the region. Precipitable
water values jump from 0.50 inches to 1.00 inches after midnight.
Priming our area for showers. The main forcing mechanism will be
from a weak elongated cold from extending from a broad low pressure
system in southwestern Quebec. This low travels rapidly east aided
by a 110 kt upper level jet located over the Great Lakes. As such
scattered showers will likely be quick moving only permitting 0.10-
0.20 inches of accumulation at the most. Temperatures overnight
Saturday night into Sunday should be mild remaining in the low
50s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
A chance of showers lingers during Sunday morning as an occluded or
weak cold front exits to the south and east. This will lead to
partial clearing and dry conditions in the afternoon. Westerly winds
through the boundary layer should allow mixing up to 850mb where
temps are forecast to be 9-10C. Not confident to go with "full sun"
potential highs, but mid to upper 70s seem reasonable for parts of
the city and NE NJ. The rest of the forecast area likely ends up
mostly 70-75, but WSW winds over/near the Twin Forks and SE CT
should hold temps in the 60s.
The SE progression of the frontal boundary to our south will be
fairly slow, and some models indicate an increase of moisture
convergence along this boundary Sunday night. This will bring a
chance of rain Sunday night, with the higher chances being over
southern portions of the forecast area.
A cold front drops south through the region most likely during the
morning on Monday, followed by cyclonic flow aloft as shortwave
energy sharpens a longwave trough over the Northeast. Moisture is
fairly limited throughout the day, but cannot rule out a shower at
any point through the day with these features. High temperatures
will return to near normal.
High pressure builds back in for Tuesday with a dry day and highs
around 5 degrees below normal. Models are then split regarding the
position of low pressure emerging off the East Coast Tuesday night
into Wednesday morning. Will introduce a slight chance of rain for
the time being for Tuesday night and Wednesday. High pressure then
builds for Thursday and lasts at least into part of Friday with
highs generally in the 60s.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Low pressure moves east of the region tonight with high pressure
to follow through Saturday.
VFR conditions expected through the TAF period. Only exceptions
would be a low chance for MVFR for KISP, KBDR and KGON before
08Z as well as a low chance for MVFR late in TAF period with
showers ahead of next low pressure system.
Winds will become more NW and increase a few kts late tonight to
a 10-12 kt range. Some gusts to near 17-20 kt are forecast into
the overnight. These winds continue into Saturday and increase
slightly in the afternoon. Gusts will develop as well Saturday,
reaching near 20 kt. Winds expected to back to more W-SW for
coastal locations during the afternoon.
.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
.Saturday night...Chance of showers with MVFR possible late.
Gusts subside early.
.Sunday...Chance of showers with MVFR possible early for Long
Island/Southern CT, otherwise VFR.
.Sunday night...Chance of showers with MVFR possible, mainly NYC
metros/Long Island.
.Monday through Wednesday...Mainly VFR. NW winds G15-20kt Monday.
&&
.MARINE...
Northwest winds 10-15 kts with gusts up to 20kts are expected to
maintain their speeds overnight. Seas should remain elevated
around 7 to 10 feet overnight and 6 to 8 ft most of Saturday on
the ocean. As such the SCA remains in effect through Saturday on
the ocean. By Saturday night, seas begin to diminish below SCA
criteria and winds 10-15kts become more southwesterly.
SW winds on Sunday diminish in the afternoon, then veer NW behind a
cold front on Monday and increase. Winds and seas through this
period are expected to prevail below advisory criteria. High
pressure builds in on Tuesday with a storm passing well south of the
waters Tuesday night into Wednesday morning. The storm will shift
winds from NW to ENE, but at this point the storm still looks far
enough south to prevent winds and seas from increasing to advisory
criteria.
&&
.HYDROLOGY...
No hydrologic impacts are expected through the forecast period.
&&
.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) is undergoing
its final stages of testing, and is operating at full power.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Saturday for ANZ350-353-
355.
&&
$$
SYNOPSIS...JC/DJ
NEAR TERM...JC/DJ/JM
SHORT TERM...DJ
LONG TERM...JC
AVIATION...JM
MARINE...JC/DJ/JM
HYDROLOGY...JC/DJ
EQUIPMENT...
Area Forecast Discussion
National Weather Service Blacksburg VA
754 PM EDT Fri May 1 2020
.SYNOPSIS...
Clouds and scattered showers will gradually decrease as high
pressure builds over the region Saturday and brings a trend for
warmer temperatures this weekend. A cold front will then bring
a chance for showers and thunderstorms back to the forecast
later on Sunday, followed by cooler and unsettled conditions
through the middle of next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 754 PM EDT Friday...
The upper trough will move east tonight allowing ridging to
build in from the west. High pressure will build across
the Southeast tonight into Saturday. The HRRR and NAMnest
showed showers tapering off tonight as the upper low pulls off
to the east and instability wanes with loss of solar heating.
Made some minor adjustments to temperatures for tonight
utilizing the latest surface obs, their trends, and blended in
the NBM. Low temperatures tonight will vary from the mid 30s in
the mountains to the mid 40s in the piedmont.
As of 200 PM EDT Friday...
Satellite and radar show considerable cloudiness west of the
Blue Ridge with scattered showers. Even had some reports of wet
snowflakes down to the lower elevations. Conditions a bit better
east of the Ridge still looking partly sunny at best with some
isolated showers. Expect scattered/widely scattered showers
will persist for the rest of the afternoon and some isolated
thunder can not be ruled out especially across the piedmont.
Showers will then diminish this evening as the upper low pulls
off to the east and instability wanes with loss of heating,
through some upslope showers will linger for a bit in the
mountains. Winds will also remain blustery before lessening this
evening. Anticipate a chilly night but believe there will be
enough wind to mix the air to avoid frost/freeze issues.
High pressure builds over the Appalachians and central mid
Atlantic region Saturday with quiet and warmer conditions to
start the weekend.
Temperatures tonight will generally be in the lower 40s east of
the Ridge, mid/upper 30s to the west. Highs on Saturday will be
in the low/mid 70s east, upper 60s/near 70 west.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 200 PM EDT Friday...
Approaching low pressure from our NW Saturday night will start to
increase moisture aloft, brining clouds in starting off for our WV
counties. As this low/front approaches, high pressure to our south
shifts off the coast/moves further south. This makes way for the
front to arrive late Sunday into Sunday night. While timing of it is
not agreed on, all guidance does agree that this line starts to dry
up as it pushes through the region, meaning the west will receive
the greatest rainfall (~.5"). Overall, there looks like there should
certainly be some thunderstorms mixed in with this front with
~500J/KG of CAPE and modest shear. However, it looks like the two
players will be out of phase with shear decreasing when instability
increases. Because of this, no foreseeable severe risk, just general
thunderstorms.
After the front passes, it stalls to our south, so cloud coverage is
still questionable for MOnday. With this update I am going with the
optimistic side and mostly clearing everyone out for a majority of
Monday, but its possible for clouds to hang out both on the
southern side and along the western slopes. Temperature wise Monday,
we do cool off slightly from the front...but not by much since it
will barely have just made it south of us.
A new system approaches from our west Tuesday, looking to first
bring a warm front into the region early in the day. This will bring
our first round of rain for the day. Our second round will come
later in the day when the associated cold front arrives. This is
another scenario where overall, it looks like we should just get
some thunderstorms out of the system. Likewise, the front looks to
become more anemic as the low shifts northward, meaning decreased
rainfall for the east.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 200 PM EDT Friday...
Thanks to Tuesday`s system, cooler weather arrives for the remainder
of the forecast. 50-70 will be the highs and lows will be mid 30s to
mid 40s after Tuesday night. That said, with the growing season
started in the west now, frost/freeze headlines look possible at
this point for Wednesday and Thursday AM.
Current temperature look warm enough at the moment that most upslope
showers that develop Thursday on the backside of Tuesday`s system
will be rain showers, but a few high elevations could maybe get a
few flakes, similar to what we are seeing today.
Another system is poised to arrive mid to late day Friday, bringing
a new round of rain, but not before helping try to usher in a warmer
airmass ahead of it.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 739 PM EDT Friday...
Expect VFR conditions to dominate east of the Blue Ridge while
MVFR holds tough to the west with IFR for the higher elevations
into KBLF. Scattered showers or pocket of drizzle will linger
into this evening, then gradually taper off tonight into
Saturday morning. Conditions will become VFR at all sites
Saturday morning and continuing into Saturday afternoon.
Gusty winds this evening will subside with loss of heating
tonight. Generally light winds overnight, though still some
gusts may linger on the hilltops.
Medium confidence in ceilings,visibilities and winds during the
taf period.
Extended Aviation Discussion...
An upper disturbance across the midwest will race eastward
and push a west-east oriented frontal boundary into the TN
Valley and Mid-Atlantic region Sunday. There are considerable
differences with respect to how far south the front will travel
before stalling in the zonal flow aloft. GFS stalls the front
across the region Sunday-Monday awaiting another disturbance by
Tuesday. Meanwhile, the ECMWF pushes it further south into the
Carolinas before it stalls. This leaves us with an unsettled
pattern. Temperatures and dewpoints rise enough to result in a
rather unstable air mass in place by Sunday afternoon. CAPES
could be near 1000 J/KG and scattered thunderstorms Sunday
afternoon seem like a good possibility given either the GFS or
ECMWF scenario at that point.
Expect VFR conditions much of Sunday in the east to MVFR in the
west, but greater likelihood of convection and sub- VFR
conditions throughout the area Sunday afternoon. Wind does not
appear to be an issue through the period with no major low/high
pressure areas expected to impact the area.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...MBS
NEAR TERM...KK/MBS
SHORT TERM...RR
LONG TERM...RR
AVIATION...KK/MBS