Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/27/20
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
519 PM CST Wed Feb 26 2020
.SHORT TERM...(This evening through Thursday)
Issued at 212 PM CST Wed Feb 26 2020
There are a couple things to note on visible satellite imagery
this afternoon. The first is the heavy snow band that occurred
early yesterday morning from near Lexington down through Osborne
county. Aside from this band, nearly all of the other snow has
melted, thanks to plenty of sun and temperatures in the 30s. The
other thing to note is the fair weather cumulus that has has
developed over the area this afternoon. This should dissipate as
we head into the late afternoon hours.
High clouds will increase again late tonight as a lower amplitude
shortwave drops out of Canada and into the northern Great Plains.
As a result, overnight lows should be 5-10 degrees warmer than
last night.
This shortwave now appears that it will provide enough lift and
moisture for some light precipitation across at least the eastern
half of Nebraska and Kansas. HRRR model soundings also show
favorable low-level lapse rates which would enhance the potential
for showers. Depending on exact timing, precipitation could
briefly begin as snow tomorrow morning, but should quickly change
to rain as near-surface temperatures rise above freezing.
Along with the showers, we should also have some stronger
northwesterly winds tomorrow. Bufkit profiles show a good
unidirectional wind profile in the low levels...likely leading to
gusts in the 25-35 MPH range. So, all in all, it won`t be a super
nice day, despite high temperatures returning to the 40s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 212 PM CST Wed Feb 26 2020
Breezy northwest winds will continue into Friday, but decreasing
clouds should allow temperatures to push into the 50s for most of
the area.
We will see the warming trend continue on Saturday as upper level
ridging amplifies over the central Plains. High temperatures have
been nudged up another few degrees, with most of the area now
expected to reach the 60s. Wind speeds are a little bit
questionable for Saturday, though. The overall model consensus is
for relatively light winds, but the latest GFS has southwest winds
sustained in the 20-25 MPH range. This is something we will need
to keep an eye on for fire weather potential.
The warmest air shifts a bit south and east and winds become
northerly on Sunday as the next approaching system forces a cold
front into the area.
Chances for rain and snow then arrive with this system late
Sunday night into Monday. Minor snow accumulations appear
possible, but this shouldn`t be a high-impact event. Low-end
chances for precipitation continue through Monday night and
Tuesday, but the GFS and Euro are in pretty good agreement that
any notable precipitation will be well south of the area during
this timeframe. More chances for rain and snow return Tuesday
night into Wednesday as another trough approaches from the
northwest. Despite all these precipitation chances, there isn`t a
strong signal for anything heavy or for a significant snow.
Beyond that, it looks like we will continue to see the near-to
above normal temperatures continue (daily highs in the mid 40s to
50s) as we finish up next week.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Friday)
Issued at 506 PM CST Wed Feb 26 2020
Cloud cover will increase lower tonight with prevalent cloud cover
expected thru much of the day Wednesday. Cloud heights will
primarily be at VFR, but have a included a period of MVFR
ceilings from around mid morning until early/mid aftn. Short term
models suggest the potential for some light precip
potential...mainly a sprinkles/showers and have included the
potential for VCSH for both KGRI and KEAR. Wind speeds will
increase during the day from the northwest as mixing deepens with
wind gusts around 25kts expected.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Fay
Area Forecast Discussion
National Weather Service Miami FL
633 PM EST Wed Feb 26 2020
.Aviation...
Instability, ahead of an approaching cold front is causing
showers across South Florida, which, are at times, bringing IFR
conditions to the region. The frontal passage is forecast to be
through the overnight hours, and besides bringing a wind shift to
the northwest, should begin to clear out the showers by the mid
morning hours for the area, with the southeast portion being the
last to clear out. Once the front pushes out, conditions are
forecast to improve through the day tomorrow.
&&
.Prev Discussion... /issued 304 PM EST Wed Feb 26 2020/
Short Term...
Remainder of Today through Tonight...
The much anticipated cold front will continue to move SE towards
South Florida throughout the remainder of today and throughout the
overnight hours. Showers will continue to increase in coverage, with
scattered to numerous PoPs spreading from west to east. A few
embedded thunderstorms are also possible with this front, though
better supportive dynamics reside to the north of the CWA.
Regardless, will have to monitor as we continue throughout the
afternoon hours and go into the overnight hours.
Looking at SSCRAM, forecast soundings, forecast derived PW`s, and
the modified RAOB sounding, the potential for an isolated damaging
wind gust is certainly there with this activity. The most notable
areas denoted by the aforementioned data sources are the Lake Region
and eastern Palm Beach County (along with all the local waters). The
possibility for higher pockets of PW are also hinted at across urban
Palm Beach County. Models are hinting at MUCAPE and DCAPE values of
~1400J/kg and 800 J/kg, respectively, also spreading from west to
east with the frontal boundary. In the end, some stronger
showers/storms may produce gusty winds with the overall severe
weather potential appearing to be low for the majority of the
region.
One other thing to watch is the possibility for minor localized
flooding across urban areas. Both the NAM and the HRRR anticipate
the 0-3km bulk shear to remain parallel to the showers/storms that
develop, allowing for the increased potential for heavier rainfall
at times. This in combination with increased moisture advection
across the region will aid in the potential for heavier rainfall.
By tomorrow morning, the front pushes offshore into the Atlantic
waters. In its wake, a much cooler airmass advects into the region
from the north. Temperatures will drop off tonight behind the front
with several inland locations dropping to the 50s. Even during the
day tomorrow, a decent drop will be felt with high temperatures
struggling to reach the 70s.
Long Term...
Thursday night through Tuesday...
A strong ridge of high pressure over the Gulf of Mexico will
dominate the weather pattern across South Florida through the end
of the work week. This will allow for a north to northwesterly
flow across the region which will bring in colder and drier air
during this time frame. Low temperatures on Thursday night into
Friday morning will drop into the upper 30s across the
northwestern interior to the 40s across the rest of South Florida.
The only exception to this will be along the immediate east coast
where lower 50s are possible.
On Friday and Saturday, the cold air advection will remain in
place as the area of high pressure over the Gulf of Mexico slowly
moves eastward. High temperatures on each of these days will
remain in the mid to upper 60s across northern and eastern areas
to around 70 across the southwestern interior sections. Low
temperatures will remain on the chilly side for Saturday and
Sunday morning as they will drop to around 40 across the
northwestern interior section to around 50 across the east coast.
By the early portion of next week, both of the GFS and the ECMWF
show this area of high pressure moving eastwards over South
Florida and into the western Atlantic. This will help to shift the
winds to a more east to southeasterly direction which will create
moderating temperatures throughout this time frame. The dry air
mass will remain in place as high temperatures climb up into the
mid to upper 70s across the east to coast to the lower 80s across
the interior and west coast sections.
Marine...
Winds and seas will continue to increase across all South Florida
waters today into tonight as a cold front approaches the region. A
Small Craft Advisory is in effect for all waters off Palm Beach
County this afternoon with the offshore waters of Broward and
Miami- Dade counties starting tonight. Then the rest of the
Atlantic waters join the Small Craft Advisory early Thursday
morning. Furthermore, all the Gulf waters have a Small Craft
Advisory going into effect early this evening. For the remainder
of the local waters, Lake Okeechobee and Biscayne Bay, Small Craft
Should Exercise Caution.
Behind the front, winds and seas remain on the higher side before
subsiding early this weekend. However, with a second shot of cold
air moving southward, winds/seas may pick up to cautionary or SCA
thresholds once again on Sunday.
Beach Forecast...
High Risk for rip currents along the Palm beaches today with a
Moderate Risk for the remainder of South Florida beaches as winds
and swells remain somewhat favorable. Behind the front, the
potential for elevated rip currents will remain across all beaches,
especially for the Gulf Coast beaches as winds will have a westerly
component.
&&
.Preliminary Point Temps/PoPs...
West Palm Beach 58 68 47 67 / 50 0 0 0
Fort Lauderdale 61 69 51 68 / 60 0 0 0
Miami 61 69 49 68 / 70 0 0 0
Naples 57 67 46 66 / 60 10 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 7 PM EST this evening for FLZ168.
AM...Small Craft Advisory from 10 PM this evening to 7 PM EST
Thursday for AMZ651-671.
Small Craft Advisory until 7 PM EST Thursday for AMZ650-670.
GM...Small Craft Advisory until 7 PM EST Thursday for GMZ656-657-676.
&&
Aviation...13
Area Forecast Discussion
National Weather Service Blacksburg VA
840 PM EST Wed Feb 26 2020
.SYNOPSIS...
A strong cold front will move through the region tonight
bringing strong gusty winds, sharply colder temperatures,
rain, followed by mountain snow showers. Thursday will be windy
and much colder. A secondary cold front will reinforce the cold
air over the weekend with additional snow possible in the
mountains. Warmer temperatures will finally return during the
first half of next week as the cold high pressure moves east out
of the area.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 840 PM EST Wednesday...
Posted a high wind warning for Grayson,Ashe and Watauga
counties until 7 pm Thursday. The 18z NAM,23z RAP and 23z HRRR
and some lamp were trending towards stronger winds in the
southwest mountains. Boone and Blowing Rock in Watauga county
were gusting to around 46. The timing of the convection looks on
track to exit the east. Then upslope snow showers and snow
flurries expected. A secondary surface low was in the process of
forming near Charlotte VA. This feature will move northeast
tonight. The cold front will continue to move east tonight into
Thursday. The cold air is arriving quickly in the west with
gusty west winds. Bluefield in West Virginia is reporting light
snow. Will have to wait until 00z model runs before making any
snow adjustments.
As of 620 PM EST Wednesday...
Made some adjustments in temperatures for this evening to
capture the colder air. Some places are expecting a 7-10
degrees drop in around 30 minutes. More changes later tonight...
As of 245 PM EST Wednesday...
Strong cold front moving through the region tonight will be the
main story ending the nice, mild, calm weather we have had the
past few days with rain, snow, wind, and sharply colder
temperatures. The cold temperatures will be reinforced over the
weekend, with a secondary cold front and a clipper system.
After looking through the HIRES near term and short term
models, am convinced with the rapidly falling temperatures,
change over of precipitation type from rain to snow fairly
quickly with strong cold low-level advection this evening, that
additional counties needed to be included in the Winter Weather
Advisory. Thus, added Tazewell, Mercer, and Summers (mainly for
the western part). Eastern Greenbrier, Monroe, Giles, and Bland
may need to be added later, but snow amounts in these counties
should remain less than 2 inches and be more spotty and limited
in time. A flash freeze is also a possibility. The combination
of rain to snow, wind, and rapidly falling temperatures will
make for a very unpleasant evening weatherwise, especially
considering the nice conditions in place now. Be prepared for
some rapid changes this evening and overnight! Snow showers will
likely continue across the mountains, especially western
Greenbrier county into the morning Thursday. Am not convinced
yet that accumulations will reach warning criteria. Those
amounts appear as if they will remain further north into
Pocahontas, but this is something that will need to be watched
during the overnight hours. Further south, have stayed with the
3500 ft. elevation level for snow in agreement with GSP.
However, this is also something that will need to be carefully
watched overnight, as 3000 or 2500 ft. may be more appropriate.
In addition to the expansion of the WSW, also added several
counties near the Blue Ridge to the Wind Advisory to match up
with LWXs Blue Ridge Wind Advisory. Wind gusts at the higher
elevations, mainly later tonight and Thursday could be in the 45
to 50 mph range.
The other concern will be the actual QLCS expected later this
evening with the possibility for gusty winds and brief heavy
rain. Wind is the main concern, and especially for the Piedmont
areas where SPC has indicated a marginal risk for severe. CAPES
are very low and model crosssections suggest that tops will
generally be too low (~15,000 ft.) for much if any lightning.
/Confidence in Forecast Parameters/
Temperatures - Moderate to High,
Precipitation Probabilities - High,
Winds - Moderate to High.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 130 PM EST Wednesday...
A deep upper level trough will cover the United States east of the
Mississippi River throughout this forecast period. As a result,
there is high confidence in a prolonged stretch of cold air
advection from northwest flow. The models are coming into better
agreement with the next round of upslope activity expected after
sunrise on Friday. Both the GFS and the ECMWF bring a shortwave
trough spinning around the periphery of the main upper level trough
across the Mid Atlantic. This shortwave trough will provide enough
synoptic lift to combine with orographic lift for snow showers to
develop along and west of the Blue Ridge on Friday. The moisture
should slowly retreat westward by Friday night but linger across
southeast West Virginia and the northwest North Carolina mountains
into Saturday. Meanwhile, breezy conditions will continue with
occasional gusts up to 35 MPH in the higher elevations. The upslope
moisture and accompanying northwest winds will eventually subside on
Saturday night as high pressure builds overhead.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 130 PM EST Wednesday...
The deep upper level trough should lose its grip over the eastern
United States by Sunday and head offshore. High pressure overhead
along with rising upper level heights will yield a recovery in
temperatures for the early part of the week. As high pressure passes
off the coast during Monday, a low pressure system should develop
across the central Mississippi River Valley. Its associated warm
front should stretch eastward to the Appalachian Mountains during
Monday afternoon through Tuesday to bring increasing warm air
advection and a chance of rain showers. The main cold front with
this low pressure system along with the heaviest bulk of moisture
will wait until Wednesday to cross over the Mid Atlantic.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
As of 629 PM EST Wednesday...
A strong cold front will move through the region tonight into
Thursday. A band of convection or squall line is expected to
accompany the front this evening into tonight. This squall line
should work toward the eastern part of the CWA by 04Z. Brief
very heavy rain and strong gusty winds (potentially 50kts) will
be possible with this squall line/QLCS through the evening
hours, especially east of the Blue Ridge when SPC has indicated
a marginal risk for severe.
The remainder of the night will feature strong gusty northwest
winds, sharply falling temperatures, and accumulating snow
showers in the mountains spilling briefly into areas such as the
New River Valley and the Alleghany Highlands. Winter Weather
Advisories and Wind Advisories are in effect for several
counties along/west of the Blue Ridge. Snow showers will
result in quickly varying visibilities.
Winds turn from southwest to west after fropa with gusts over
30kts across the mountains/foothills. Snow showers with
visibilities in the IFR range expected at times west of a LWB-
BLF line, with potential sub-VFR cigs/vsbys as far east as BCB
overnight.
Conditions will become VFR overnight east of the Blue Ridge with
little if any snow showers, but gusty northwest winds for sure.
West of the Blue Ridge, and especially across the western
mountains, expect sub-VFR conditions much of the night with
visibilities severely reduced in the heavier snow showers.
Medium confidence in ceilings,visibilities and winds during the
taf period.
Extended Aviation Discussion...
Thursday will see gusty winds persisting through the day with snow
showers winding down in the west with sub-VFR becoming VFR in
the afternoon. Another disturbance and clipper allows for more
sub-VFR cigs and possibly vsbys Friday afternoon/evening with
snow showers in the mountains, but should be mainly VFR east.
VFR returns for most for the weekend as high pressure moves in.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Wind Advisory until 7 PM EST Thursday for VAZ007-009>014-
016>020-022>024-032>035.
High Wind Warning until 7 PM EST Thursday for VAZ015.
Winter Weather Advisory until noon EST Thursday for VAZ007-015.
NC...Wind Advisory until 7 PM EST Thursday for NCZ002.
High Wind Warning until 7 PM EST Thursday for NCZ001-018.
Winter Weather Advisory until noon EST Thursday for NCZ001-018.
WV...Winter Weather Advisory until noon EST Thursday for WVZ042-043-
508.
&&
$$
SYNOPSIS...RAB
NEAR TERM...KK/RAB
SHORT TERM...PW
LONG TERM...PW
AVIATION...KK/RAB