Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/21/24
Area Forecast Discussion
National Weather Service Cheyenne WY
833 PM MST Tue Feb 20 2024
.KEY MESSAGES...
1) Strong winds will continue to diminish over the eastern
plains this afternoon and evening.
2) Another round of mountain snowfall for south central Wyoming
Tuesday night through Thursday. Areas along I-80 in Carbon
County may also see at least 3 inches of snow from this event.
3) Unsettled weather continues with strong winds expected over
the weekend and into early next week.
&&
.UPDATE...
Issued at 829 PM MST Tue Feb 20 2024
Looking at latest SNOTEL reports in the Sierra Madre
Range...getting some pretty hefty hourly SWE reports. Latest RAP
simulated radar showing band of heavy snow continuing over
WYZ112 through at least tomorrow afternoon. This mesoscale
guidance looking to be handling the current situation the best. Decided
to upgrade the Winter Weather Advisory to a Winter Storm
Warning for the Sierra Madre for an additional 15-19 inches of
snow through that time. Updates sent.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 125 PM MST Tue Feb 20 2024
The primary forecast challenge tonight through Wednesday night
will be with regard to snow over southeast Wyoming. This event
will be driven by strong upper-level jet dynamics, with the core
of the jet positioned just to our south over the Central
Rockies on Wednesday. Underneath this jet, a stream of Pacific
moisture will traverse the Central Rockies, with PWAT normalized
anomalies on the order of 1 to 2 sigma from tonight through
Wednesday afternoon. Confidence in the first half of this event
remains rather high. Short-term high-res ensemble guidance
favors broad upslope snows in the Sierra Madre and Snowy range
starting this evening, with more diffuse banded snow drifting
northward through Carbon and Albany counties through the early
morning hours after midnight. Nearly every ensemble member
depicts this solution. A brief lull in precipitation, especially
over the valley locations, is likely in the 3am to sunrise
timeframe before favored jet dynamics and moisture drift back
south over southeast Wyoming. Another round of moderate to
possibly heavy snow is all but guaranteed in the mountains,
however what happens in the high mountain valleys is still a bit
uncertain. The HRRR and FV3 (and to some degree the operational ECMWF)
depict quite a bit of CSI-driven banded snow across Carbon,
Albany, and even portions of western Converse, Platte and
Laramie Counties. Other high-res guidance such as the NSSL and
NAM Nest are less enthusiastic about this outcome and as a
result depict much lower snow totals outside of the higher
terrain. Cloud cover and convective snow trends during the day
on Wednesday may ultimately determine the outcome, with some
areas remaining just a bit too warm with low snow rates to
accumulate much outside of any banding or brief squall activity.
Given the rather consistent nature of run- to- run HRRR and
ECMWF guidance, have opted to issue a Winter Weather Advisory
for portions of West- central and east- central Carbon County
along I-80 for this event. For now, these areas appear to be the
highest confidence for Advisory-level snow outside of the
mountains. As forcing and moisture shift southward on Wednesday
night, snow will gradually taper off. A few isolated snow
showers may linger in the higher terrain as moisture does not
quite clear out in the mid-levels. As such, the surface
temperature forecast is not quite as cold as it could be if we
see clearing a bit earlier.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 125 PM MST Tue Feb 20 2024
Northwest to west-northwest flow aloft will dominate the upper-
level pattern through the long-term. At the surface, expect
mainly dry weather through the period, except for one brief
window of light snow in the higher terrain on Thursday afternoon
and evening as a weak wiggle/wave in northwest flow passes
through. Attention turns to the wind forecast as favorable flow
aloft and gradients across the CWA strengthen by the weekend.
Currently appears as though two windows for high winds will
exist, with the first on Friday night into Saturday morning
primarily over the western wind-prone corridors and the other on
Sunday morning into the afternoon across both the Snowy Range
foothills as well as east of the Laramie Range in the typical
gap flow area between Chugwater and Wheatland. In-house machine
learning guidance supports this trend once again today, with
moderately high probabilities of exceeding 60 knots in the
aforementioned areas on Sunday morning through Sunday evening,
and even into early next week.
Overall, temperatures will remain rather mild with above average
weather continuing right through Monday of next week. In fact,
temperatures in the mid to perhaps upper-50s are possible east
of I-25 each day from Saturday through Monday. Ensemble guidance
continues to indicate the potential for a cool-down on Monday
evening into Tuesday morning of next week, accompanied by heavy
snow in the mountains and perhaps some light snow east of the
Laramie Range. However, ensemble guidance is quite dispersive
with precipitation amounts east of the Laramie Range at this
time, with some members even indicating a dry frontal passage.
What is more certain is that heavy mountain snows are likely on
Monday into Tuesday, with a general overall cooldown from Monday
night through the middle of next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 407 PM MST Tue Feb 20 2024
Mainly VFR conditions expected across southeast Wyoming and
western Nebraska over the 00Z TAF period. Gusty winds have
continued to decrease and will continue to decrease further
overnight. Light rain becoming snow showers are forecast to move
in from the west affecting KRWL after 03Z with MVFR to IFR CIGS
and VIS. Confidence is low currently on the exact location of
the rain/snow showers, but they could potentially affect KLAR,
KCYS, and KCDR later tomorrow afternoon.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 11 PM MST Wednesday for WYZ109-
110.
Winter Storm Warning until 5 AM MST Thursday for WYZ112.
Winter Weather Advisory until 5 AM MST Thursday for WYZ114.
NE...None.
&&
$$
UPDATE...GCC
SHORT TERM...MAC
LONG TERM...MAC
AVIATION...LEG
Area Forecast Discussion
National Weather Service Quad Cities IA IL
1000 PM CST Tue Feb 20 2024
.KEY MESSAGES...
- Quiet and warmer than normal weather to continue much of the week.
- Low rain chances south Wednesday night into Thursday morning.
- Potentially more active during the last week of February.
&&
.UPDATE...
Issued at 955 PM CST Tue Feb 20 2024
Added POPs into Wednesday evening along to the I80 corridor.
Three consecutive synoptic hour runs of the HRRR have convection
forming across this area between 03z and 06z. While latest
guidance has backed off on intensity, it still has it. With
guidance under-forecasting thermo fields as of late, have
decided it better to acknowledge the signal and increase
thunderstorm percentages. If the 12Z HRRR is correct, we could
see some elevated hailers Wednesday evening.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 143 PM CST Tue Feb 20 2024
Plentiful sunshine, with only a few clouds over east central
Iowa, was seen areawide today thanks to strong ridging aloft in
place over the Midwest and Great Lakes. This ridging, combined
with breezy south winds, helped afternoon temperatures soar well
above normal, with values currently ranging from 52 in
Independence to 62 in Macomb.
Over the next 24 hours our primary concerns will be exiting ridging
and increasing upper level cloud cover from the west, which will
mainly impact temperatures. Expecting lows tonight to only drop into
the mid to upper 30s with the help of a light south wind. Wednesday,
another above average day is expected with highs in the upper 50s to
low 60s. Some guidance is a little higher with temps, but decided to
continue the theme of the previous shift in holding back temps
thanks to the increased cloud cover.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 143 PM CST Tue Feb 20 2024
Thursday...
Weak frontal boundary will pass across the region, and will usher in
northwest flow. This will also follow a progressive mid-level
shortwave, which will bring a chance of showers and thunderstorms to
portions of the area. At this time, southeast Iowa, west central
Illinois and northeast Missouri will have the highest chance (20-
40%) of precipitation as it will be nearer to more favored lift with
the shortwave and the concurrent upper level jet. However, the bulk
of QPF should remain southeast of the area.
Friday...
Cooler day (albeit with above normal temperatures) is expected to
close out the work week with weak high pressure passing through the
Plains and Midwest. There remains a signal for a clipper-like
shortwave to pass through the area during the afternoon and evening,
though there is a lack of moisture with this feature. Look for highs
only in the 40s, to perhaps low 50s in northeast Missouri.
The Weekend...
A very nice weekend is in store with a renewed round of Canadian
high pressure moving into the region. We start out cool, but rebound
nicely in temperatures Sunday as the high pushes east and robust
ridging aloft builds across the central U.S.. Temperatures start out
Saturday in the 40s/50s, but surge into the 60s for most Sunday.
Monday onward...
This surge of warm air will not go unnoticed by mother nature, with
latest guidance suggesting a return to active weather by late Monday
and Tuesday with the approach of a frontal boundary. Showers and
storms will be possible, though exact details are hard to hash out
this far in advance. Temperatures look to be the warmest of the year
so far with highs for some approaching 70!
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 552 PM CST Tue Feb 20 2024
VFR conditions expected through the period with winds under
10kts. NO sig wx impacts to aviation expected.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
UPDATE...Gibbs
SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Gibbs
Area Forecast Discussion
National Weather Service Fort Worth TX
518 PM CST Tue Feb 20 2024
...New Aviation, Short Term...
.SHORT TERM... /NEW/
Update:
Plenty of sun and subtle adiabatic warming pushed temperatures
into the 70s to the middle 80s with some locations, including DFW,
reaching 80 or above for the first time in 2024. However, it
actually has not been that long since DFW reached 80 degrees
(December 8th, 2023).
We still expect warm air advection to continue tonight into
Wednesday. The low level jet that sets up tonight will have a
southwesterly direction, keeping the potential for stratus and
patchy fog generally east of the I-35 corridor. We will not make
any significant changes to the current forecast (see discussion
below) but will bump Wednesday highs up a few degrees area-wide
based on today`s temperature trends and the cloud cover, or lack
of, we expect tomorrow.
79
Previous Discussion:
/Through Wednesday/
Quiet, rain-free weather continues through Wednesday as we remain
beneath a mid-level ridge. Afternoon temperatures will top out
10 to 20 degrees above normal today, with highs in the mid 70s to
mid 80s. The pressure gradient will compress across North and
Central Texas this afternoon as a low pressure system intensifies
in the lee of the Rockies. This will result in the onset of breezy
conditions that will continue through Wednesday. Wind speeds will
increase to 10 to 15 mph this afternoon with a few gusts between
20 to 25 mph.
Patchy fog is expected to develop late tonight into Wednesday
morning, but a surge of low stratus adds some uncertainty to this
forecast. The area highlighted for patchy fog was expanded further
north with this update, but still excludes most of the Metroplex
at this time. It`s possible we end up with only low stratus and
no (or very little) fog, but uncertainty is still quite high.
Regardless, any fog should dissipate by mid to late Wednesday
morning, with some lingering stratus expected east of I-35 through
midday/early afternoon.
Guidance has slightly backed off on the hotter temperatures
tomorrow, mainly across the Big Country. NBM probabilities now
only advertise about a 5-10% chance of reaching 90 degrees in this
region. Therefore, temperatures were lowered slightly from the
previous forecast. Nonetheless, Wednesday is still expected to be
another warm February day with afternoon highs ranging from the
mid 70s across the east to mid 80s across the west. Slightly stronger
winds are expected tomorrow, with sustained speeds mostly between
15 to 20 mph and gusts upwards of 30 mph.
Barnes
&&
.LONG TERM... /Issued 211 PM CST Tue Feb 20 2024/
Update:
No major changes were made to the long term forecast. Upper-level
ridging will continue our above-normal stretch of temperatures
through much of the week and into next weekend. A weak, rain-free
cold front will sweep through North and Central Texas on Thursday,
but temperatures will remain slightly above-normal as this cooler
airmass modifies along its journey south. Temperatures will go on
the rise once again over the weekend and into the start of next
week as highs climb into the upper 70s and low 80s, with rain
chances remaining just out of reach of the extended forecast.
Reeves
Previous Discussion:
/Wednesday Night Onward/
The ridge at least partially responsible for the nice, warm
weather will weaken Wednesday night and Thursday as a shortwave
trough propagates east across the Plains. The trough will drag a
cold front through North and Central Texas on Thursday, bringing a
slight cool-down for the latter half of the week. Daytime
temperatures will drop from 15-20 degrees above normal on
Wednesday to 5-10 degrees above normal on Friday, with Thursday
being the transition period as the front sweeps through. A tight
pressure gradient associated with
the surface frontal system will
create windy weather both Wednesday night ahead of the front and
Thursday behind the front.
A warm-up will then ensue this weekend as return flow arrives and
a mid/upper ridge redevelops overhead, with temperatures climbing
to 10-15 degrees above normal by Sunday. South winds will
strengthen late Saturday and remain gusty through Monday as the
next upper trough approaches and lee-side surface troughing
intensifies. The upper trough and its attendant cold front will
bring our next chance of rain around the middle of next week,
followed by cooler and dry weather late next week to round out
February and begin the month of March.
30
&&
.AVIATION... /NEW/
/00Z TAFs/
No significant aviation weather concerns are expected through the
evening with south flow and only some passing high clouds.
A 30+ knot low level jet will develop late this evening, sending
a deck of stratus northward. The southwesterly direction of the
low level jet should keep the bulk of the low clouds generally
east of I-35/I-35E as per the HRRR solution, but Waco should be
right on the edge. Therefore, we will continue to show low end
MVFR ceilings in Waco between 11Z and 15Z. A very temporary
ceiling is possible at DAL but confidence is too low to include.
Some patchy fog is also possible across the east and southeast
where low level moisture will be most plentiful but no visibility
restrictions are anticipated at the TAF sites.
A south wind will prevail between 11 and 17 knots along with some
gusts near 30 knots, especially Wednesday afternoon.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 55 77 59 75 49 / 0 0 0 0 0
Waco 56 75 59 79 49 / 0 0 0 0 0
Paris 54 74 59 74 46 / 0 0 5 0 0
Denton 53 77 56 74 44 / 0 0 0 0 0
McKinney 54 75 58 75 46 / 0 0 0 0 0
Dallas 57 77 61 76 50 / 0 0 0 0 0
Terrell 55 74 58 76 47 / 0 0 0 0 0
Corsicana 57 75 60 80 50 / 0 0 0 0 0
Temple 55 75 58 80 49 / 0 0 0 0 0
Mineral Wells 51 83 55 74 45 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
902 PM EST Tue Feb 20 2024
.Key Messages...
- Warm and dry through Wednesday
- Continued warm with rain Wednesday night into Thursday, with
isolated storms Thursday.
- Brief cooldown early in the weekend.
- Temperatures back to well above normal early next week with
showers and storms late Monday into Tuesday. Severe and flood
threats being monitored.
&&
.Forecast Update...
Issued at 859 PM EST Tue Feb 20 2024
Some mid to upper level clouds are stating to progress into
centralIndiana within a modest upper level jet. This should be
the only cloud cover overnight as central Indiana remains heavily
influenced by broad low level subsidence. Winds are still expected
to remain steady between 5-7kts out of the S overnight.
Temperatures could once again overperform guidance as the PBL
depth expands beneath subsidence and dry air mixing ensues in the
afternoon. Highs in the low to mid 60s are likely across the
region.
&&
.Short Term...(This evening through Wednesday)
Issued at 302 PM EST Tue Feb 20 2024
The short term is generally quiet as surface high pressure resides
over the region. Satellite imagery shows a compact vort max passing
just to our southwest. Aside from a few cirrus clouds, not much is
expected from this feature.
The primary forecast challenges today are high temperatures and dew
points/RH. High temps over-performed yesterday in a lot of places,
especially where snow cover was thinnest or already melted. Model
soundings show a very dry column with a stout warm nose just above
the surface. Given clear skies, southerly flow, and even less snow
cover...am thinking that boundary layer mixing will be optimized
today. With that in mind, adjusted temperatures from the blend using
a MOS/NBM 90th percentile combo which brings highs into the mid and
upper 50s. Kept them more in line with the blend further northeast
where snow cover remains.
That brings us to part two of the forecast challenges...dew points.
As said before, model soundings show a dry column with a warm nose
just above the surface. Mixing should be very efficient, and in
similar past situations dew points mix far below what blended
guidance suggests. These scenarios can lead to dew points as much as
10 to 15 degrees lower than forecast if not accounted for. As such,
added weight to HRRR and NBM 10th percentile to better capture
afternoon mixing potential. Again, lingering snow cover to the north
and east may limit this somewhat by reducing the efficiency of
mixing.
For tonight, went with higher res guidance on temps to account for
good radiational cooling potential. This too deviates from the
blend, but in the other direction. Temps should be slightly lower
than guidance, especially in rural areas and in low-lying
terrain/valleys. Some higher hilltops to our southwest may remain
above freezing as they poke above a shallow nocturnal inversion.
High clouds streaming in from the west could be a mitigating factor,
but should be thin enough and/or arrive too late to make a huge
difference. Additionally, the MSLP gradient tightens somewhat during
the night which may limit cooling potential to low-lying/sheltered
areas.
&&
.Long Term...(Wednesday night through Tuesday)
Issued at 302 PM EST Tue Feb 20 2024
A fairly progressive pattern is expected for the long term period,
with a couple of opportunities for widespread rainfall and perhaps a
few thunderstorms. Additionally, temperature range during the period
will be large, roughly 25 degrees between warmest and coolest highs
and lows across central Indiana.
Wednesday night into Thursday, a broad upper level wave will slide
through the region on the poleward side of 120-140kt upper level jet
streak, allowing for the development of a modest surface low.
Thermal and moisture advection ahead of this low on a fairly robust
850 jet of 30-40KT+, though the window for this will likely not be
long enough to see enough local airmass modification for more than
isolated-widely scattered embedded thunderstorms within the larger
area of rainfall, and organized severe storms are not expected.
That said, given moderately strong deep layer shear, an isolated
strong storm would not be entirely out of the question, primarily
across southwestern portions of the area Thursday.
For the most part, in the wake of the passage of this first system,
dry weather is expected through the weekend, with surface high
pressure a dominant force. One possible exception to this could be
Sunday evening, when a weak upper wave and surface boundary may be
able to produce isolated showers.
Focus then shifts to guidance signals of a developing potent mid-
latitude cyclone early next work week, which could present
convective threats from both a hydrologic and severe weather
standpoint, though timing and configuration differences amongst the
guidance suite make this a watchful waiting issue at this point.
Potent dynamics will be present, with a 50-65KT low level jet, a
large mid-upper level trough and southwesterly upper level jet
streak possibly as strong as 150-180KT, which would produce ample
deep layer shear as well as low level shear.
As is often the case in cool season events, thermodynamic factors
are likely to be the linchpin here, with potential for a broad,
open warm sector ahead of the low with plentiful poleward
thermal/moisture transport. However, subtle changes in the
surface/low level pattern could disrupt this - for example, a
lagging subtropical high off the southeastern US could limit
poleward warm sector extent, less phasing of the northern and
southern stream jets aloft would decrease overall system intensity
and mass response, and/or more intense convective activity in a
deeper/more robust warm sector to the south may help to limit
instability further north, thus reducing the extent of the severe
threat locally - all of these are common failure modes to longer
range convective threat forecasts, particularly at this time of
year, and will bear watching as we go through the next week.
Experimental machine learning severe weather guidance for days 7-8
from Colorado State University do show severe probabilities in the
area, though St Louis University CIPS analogs are focused further
southwest - but both do tend to show the centroid of highest threat
further south at this time.
Depending upon the orientation of the low level and deep layer flow
with respect to the front, a hydrologic threat is also possibly in
the cards - and ensemble hydrologic guidance has a fairly consistent
signal at this time showing potential for at least action stage
flows along the Wabash valley, with some potential for lowland
flooding in the GEFS (GEFS does tend to be the more aggressive of
the hydrologic ensembles, however). With longer term drought
resolved by last month`s precipitation and subsequent flooding, it
will not take quite as much rainfall this time around to initiate
flood concerns.
With the progressive pattern throughout the period, significant
temperature swings are expected, with warm temperatures early (above
normal) and late (much above normal) in the long term surrounding
briefly cooler (near normal) temperatures early in the weekend.
Aside from minor tweaks, NBM had a decent handle on this. While
record temperatures appear unlikely at this time, widespread highs
in the 60s appear to be a good bet early next week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 651 PM EST Tue Feb 20 2024
Impacts:
- Southerly winds of 7-10 kts through the period with gusts near 20
kts possible tomorrow afternoon at KIND
Discussion:
VFR conditions expected through the forecast period.
Generally clear skies tonight aside from a few passing cirrus.
Clouds increase towards the end of the period ahead of an
approaching system.
Winds remain southerly at 7-10 kts through most of the period with
some gusts possible tomorrow afternoon, up to around 20 kts.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Updike
Short Term...KF
Long Term...Nield
Aviation...Updike
Area Forecast Discussion
National Weather Service North Platte NE
521 PM CST Tue Feb 20 2024
.KEY MESSAGES...
- Saturday through Monday...Weather conditions appear to become
favorable for critical fire weather and Fire Weather Watches
may be issued later this week across wrn and ncntl Nebraska.
- Rainfall from scattered showers Wednesday night will be less
than 1/10 inch in most areas. Locally higher amounts are
possible. Rain or snow showers are also possible with the
arrival of a strong cold front Monday night and Tuesday next
week.
- Highs in the 60s are in place Saturday and Sunday. The NBM
50th highly suggests highs in the 70s Monday, a good 5 degrees
warmer than the current forecast.
&&
.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 327 PM CST Tue Feb 20 2024
The short term models are in very good agreement setting up east
west frontogenesis across SD/nrn Nebraska late tonight and
Wednesday. A nrn stream short wave will drop south through the
region Wednesday night and push this focus south through the region.
The models are split with some showing scattered showers and the
best QPF, mainly across the wrn Sandhills, while the
NAM12/NAMdng/HREF are further east and north with the best QPF
across nrn Nebraska and srn SD. The forecast follows WPC which, as a
compromise, places the best rain chances across the wrn Sandhills
and nrn Nebraska Wednesday night.
There should be reasonable radiational cooling across srn Nebraska
tonight where winds will be very light and skies generally clear.
Across the north, frontogenesis should increase cloud cover after
midnight. The temperature forecast leans on the guidance blend
across the south and the warmer short term model blend to the north.
Skies conditions remain mostly cloudy north and mostly clear south
Wednesday. Thus, 60s are in place for highs across the south with
50s across the north. This forecast uses the cooler short term model
blend but adds a couple of degrees to line up with the warmer RAP
model.
A well mixed atmosphere is expected with the approach and passage of
a nrn stream short wave Wednesday night. The short term model blend
keeps lows above freezing across much of the region. Lows in the 20s
are in place across just the northwest corner of wrn Nebraska and
this might be too cool given the model consensus keeps lows in the
lower 30s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 327 PM CST Tue Feb 20 2024
Dry weather is nearly certain Thursday through Monday and attention
is drawn toward the temperature forecast. The disturbance
Wednesday night will knock about 8C off temperatures at h850mb
and highs in the 50s are in place Thursday and Friday.
Temperatures at that level will begin marching upward Saturday
and peak near 12-15C Monday. 60s are in place Saturday and
Sunday. The NBM 50th highly suggests highs in the 70s Monday, a
good 5 degrees warmer than the current forecast. If the
temperature forecast aloft verifies, the NBM would likely
verify.
Today`s runs of the ECM, GFS, ICON and GEM are in good agreement
maintaining the strong system Tuesday as an open wave. The prospect
of any sort deep storm system and major impacts is off the table for
this forecast. The NBM 50th places gusts around 30 mph and this is a
good starting point. A sub 990mb sfc low will track through either
SD or Nebraska next week and the storm track is progressive. The
strong cold front progged to move through Monday night should lower
highs about 30 degrees Tuesday- h850mb temperatures fall about 15C
from the previous day.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 517 PM CST Tue Feb 20 2024
VFR conditions are expected to prevail across western and north
central Nebraska through the period. The gusty winds from today
will quickly become light and variable at 6kts or less this
evening, continuing into overnight period. Light rain showers
are possible Wednesday morning across northern Nebraska,
however, ceilings should remain at 5000 FT or higher with
minimal impacts to terminal sites expected.
&&
.FIRE WEATHER...
Issued at 327 PM CST Tue Feb 20 2024
Saturday through Monday...Weather conditions appear to become
favorable for critical fire weather and Fire Weather Watches may be
issued later this week across wrn and ncntl Nebraska.
The models are in very good lowering h850-700mb RH to 10-30 percent
Saturday through Monday. This should cause sfc humidity to fall
below 20 percent and perhaps as low as 10 percent. The culprit
is a break down of sfc high pressure across the Rockies in
response to the approach of a strong nrn stream disturbance.
Winds aloft at h700mb, the presumed mixing height, are running 30 to
35 kts in the models and this should equate to gusts of 25 to 35 mph
at the sfc.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Viken
FIRE WEATHER...CDC
Area Forecast Discussion
National Weather Service Raleigh NC
924 PM EST Tue Feb 20 2024
.SYNOPSIS...
Surface high pressure centered over the Northeast states will extend
southwestward through the Carolinas through mid week. A storm system
will cross the Mid Atlantic region late Thursday through Friday.
High pressure will build over the Southeast states for the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 924 PM Tuesday...
The 00Z upper air analysis shows the mid/upper s/w over the
Carolinas at both H5 and H7. There was a shallow layer of saturation
around 300mb, but otherwise the column was largely dry. This is
supported by GOES satellite imagery, which shows a streak of high
clouds extending SE to NW across central NC from the low offshore.
At the surface, a 1035mb high centered over the St. Lawrence river
is ridging southwestward into the mid-Atlantic and Carolinas.
Dry weather and light winds will prevail through tonight. The
lingering high clouds across the area should clear out over the next
several hours, with clear skies expected through the remainder of
the night. Low level thicknesses at 12Z Wed should be similar to 12Z
this morning, in the 1305m to 1315m range. Given the similar
conditions tonight as last night, expect lows to also be similar,
mid 20s to low 30s.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
As of 355 PM Tuesday...
A very similar day as today is in store for tomorrow, as surface
high pressure ridges down the Eastern Seaboard into the Carolinas.
NW flow aloft on the backside of a mid/upper trough in the western
Atlantic will bring sunny skies to central NC. Low-level thicknesses
near or slightly higher than today will bring high temperatures near
to a couple degrees warmer, ranging from lower-to-mid-50s in the far
NE to near 60 in the far SW. This is within a couple degrees of
normal.
Some high clouds will begin to move in overnight Wednesday night in
advance of the next trough moving into the Central Plains and mid-MS
Valley. However, they should be mostly concentrated over NW zones
with mostly clear skies elsewhere. Some short-term high-res guidance
like the HRRR shows fog will be possible in the NE and E early
Thursday morning, aided by the very light to calm winds. Despite the
high clouds, lows should still drop into the lower-to-mid-30s, with
even some upper-20s possible in outlying spots.
As the surface ridging shifts offshore on Thursday, the low-level
flow will switch to the SW, helping increase thicknesses by roughly
20-30 m. So forecast highs range from lower-60s far north to upper-
60s far south. High clouds will also be on the increase through the
day from NW to SE, becoming mostly cloudy to overcast by late
afternoon, as the upper troughing moves into the TN Valley and flow
aloft over central NC turns more zonal. Ensemble guidance is in good
agreement that any rain will hold off until at least Thursday
evening.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
As of 330 PM Tuesday...
An upper trough will dig southeast across NC late Thu into Fri,
along with the associated cold front moving across the area early
Fri. Periods of showers will develop across the area from west to
east as the trough and front approach, and a tightening pressure
gradient will create breezy winds overnight and into Friday, as
well. Winds will increase and remain south/southwesterly overnight
ahead of the front, with gusts of 20-30 mph expected. Once the front
passes by, winds will shift northwesterly and slowly diminish
throughout the afternoon. Showers will begin to exit the area
towards the east Fri afternoon. There may be enough instability
aloft for an isolated thunderstorm to develop, mainly Fri afternoon
across areas east of US-1. Rainfall amounts have remained steady,
with values near one-tenth of an inch possible across the north and
near one-quarter of an inch across the south. Confidence in the
details of timing of precip and amounts are moderate due to lagging
difference in some solutions (12Z NAM is much slower).
The forecast for Saturday has remained dry, however ensembles
continue to show and are expanding the possibility of light showers
with a weak upper wave during the day and evening. The lower levels
should remain fairly dry to prevent much, if any, accumulation, so
only sprinkles or virga is expected at this time.
Mostly zonal flow aloft develops across central NC early next week
as a broad ridge develops across the Gulf of Mexico. Surface high
pressure will build east across the Southeast through the period,
generating warm air advection across the region. Rainfall chances
slightly increase again on Tuesday as weak waves embedded in
southwesterly flow move northeast across the Plains and into the Mid-
Atlantic. Additionally, a cold front may approach the area from the
north by Tue/Wed, continuing elevated precipitation chances through
mid-next week.
Temperatures will dip to near seasonal normals Saturday behind the
cold front, then warm air advection returns, increasing highs to 10-
15 deg above normal by Monday, with temperatures in the upper 60s to
mid-70s by next Tuesday.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 619 PM Tuesday...
Through 00Z Thursday: VFR conditions expected through the TAF period
with any clouds being aoa 20k ft agl. Sfc winds will be mainly from
the NE aob 10kt.
Outlook: VFR conditions should continue through the rest of
Wednesday into Thursday, with another minimal chance for IFR clouds
(but not ceilings) at RWI Thursday morning. Rain is likely Thursday
night and Friday at all terminals with restrictions likely and gusts
between 20-30 kt. Dry VFR conditions should return Friday night and
continue into Sunday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...KC
SHORT TERM...Danco
LONG TERM...JJT
AVIATION...np/Green