Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/26/22
Area Forecast Discussion
National Weather Service Boise ID
820 PM MST Tue Jan 25 2022
Latest satellite imagery showing extensive stratus deck through
the Snake River Plain this evening and even extending up towards
Baker Oregon. Some clearing noted across southern Twin Falls
County and into Twin Falls this evening. Trends of the HRRR model
and current forecast, keeps this somewhat clear through the
evening but brings it back in during the early morning hours.
Therefore no updates planned from this afternoons package at this
time as models keep the inversion in place the next few days.
Mostly MVFR to IFR in fog and low stratus, otherwise
mostly clear at airports above 6000ft MSL. Fog and low stratus will
likely continue to expand across all valley locations overnight.
Surface winds: variable 10kt or less. Winds aloft at 10kft MSL: N-NE
10-20kt becoming N-NW 15-25kt by 12z/Wed.
A dry northerly aloft will persist through Thursday, followed by
an upper ridge Friday and Saturday. The inversion will continue
through the period and likely strengthen with the arrival of the
ridge later in the week. The inversion will finally completely
break early next week as a low pressure system moves into the
region. An Air Stagnation Advisory remains in effect for Harney
County through Friday morning.
SHORT TERM...Tonight through Thursday night...A dry north-
northwest flow aloft will continue through the period as an upper
ridge off the west coast slowly moves inland. The inversion and
resultant low stratus/patchy late night-morning fog will persist.
Little day-to-day changes to temperatures are anticipated,
averaging 5 to 10 degrees below normal. Winds will be generally
light (less than 10 mph).
LONG TERM...Friday through Tuesday...An upper level high
pressure ridge will remain over the region and maintain the
temperature inversion through the weekend, with areas of low
clouds, patchy fog, and below normal temperatures in the valleys.
A trough will move south out of the Gulf of Alaska on Monday,
bringing a cold front through the region. Snow levels will fall to
the valley floors with scattered snow showers continuing into
Tuesday. Temperatures will remain below normal across the valleys,
with above normal temperatures across the higher elevations until
the cold front arrives on Monday.
OR...Air Stagnation Advisory until 10 AM PST Friday ORZ061.
PREV SHORT TERM...BW
PREV LONG TERM....KA
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
816 PM EST Tue Jan 25 2022
A cold front will move through the area tonight, followed by cold
high pressure settling into the area Wednesday and Thursday. Another
cold front and associated coastal low will develop Friday night and
.NEAR TERM /THROUGH TONIGHT/...
As of 816 PM Tuesday...
AS of 01Z, the sfc cold front was located roughly along or just west
of the I-85 corridor and will continue to gradually shift south
overnight and will be to our east well before daybreak. No precip
is expected with its passage. N to NE low level flow will develop
behind the front (speeds around 6-10kt with a few higher gusts),
with CAA underway as a 1036 MB high centered over the northern
Plains begins to move southeastward. As of 8 PM, current temps are
in the 40s across central NC. Look for readings to gradually fall
through the mid and upper 30s overnight, with perhaps sub-freezing
temps spreading southward along the I-95 corridor (thanks to N-NE
sfc winds and CAA) during the last few hours just before daybreak.
Lows tonight will range from 32-34 west to 28-32 east. Otherwise,
latest HRRR shows a layer of 5K ft AGL stratocu developing and
spreading southeastward just behind the front overnight. This will
have little impact on the temps since tonights temps will be mostly
dependent on CAA.
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 250 PM Tuesday...
A mid-level trough over the eastern Great Lakes and upstate NY will
move off the North Atlantic Wednesday evening, followed by weak mid-
level ridging over the Mid-Atlantic by early Thursday. At the
surface, the 1035 mb arctic high pressure system over MO will drift
east and settle over the Mid-Atlantic into early Thursday. Low-level
thicknesses behind the front will be 1280-1300m, resulting in a much
colder day and temperatures around 10-13 degrees below normal in the
upper 30s to lower 40s. The low-level RH evident in forecast
soundings will favor morning low clouds, though sunshine should
start to work in for the afternoon hours. As high pressure settles
in Wednesday night, good radiational cooling with clear skies and
light winds under the arctic airmass, will promote temperatures well
below normal in the upper teens to lower 20s in most locations.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 330 PM Tuesday...
...Persistent trough Over the Eastern US will result in a chilly end
to January 2022...
...Another round of wintry weather/snow late Friday through early
Thursday and Thursday night: In advance of the strong upper level
trough digging into the Central US, another low-amplitude southern
stream shortwave will become increasingly sheared as it ejects
through the SE US. This disturbance aloft could produce some
scattered thin mid/high clouds across southern NC during the day,
followed by a marked increase in clouds Thursday night. Though
weakening/modifying, the cold surface high pressure will linger
across the area through Friday morning. Continued chilly, with highs
ranging from upper 30s/near 40 north to mid south. Lows in the 20s.
Friday and Friday night: Models are coming into better agreement and
thus forecaster confidence is increasing.
The upper trough over the central and eastern US will reload as yet
another strong, amplifying shortwave trough dives SE, potentially
deepening into a closed upper low as it moves through the Carolinas
late Friday/early Saturday. In response to the incredibly strong
synoptic scale ascent, sfc cyclogenesis will quickly spin up off the
Florida coast Friday morning and will start to undergo rapid
deepening and quite possibly bombogenesis late Friday night/early
Saturday as it races north, well off the NC coast. Since there is
now increasing model agreement that the low will be well offshore,
the onset of rain/precip has slowed down considerably, delayed until
the afternoon when BL temps and surface wet bulb temps are above
freezing. In fact, it`s entirely possible that central NC could see
very little rain from the actual coastal low. Instead, the bulk of
lift and precip will be associated with the trailing,
amplifying/deepening northern stream trough that will overspread the
area from the west/northeast Friday evening/ night, coincident with
a surface cold front that will move through the area. Latest runs of
the EC and Canadian now suggest that the trough will close off
across central NC as it moves through the area Friday night. The
resultant deep column cooling will result in a fairly efficient
change-over from rain to snow, with any transition p-type of
freezing rain/sleet being very short-lived and inconsequential. Very
preliminary snow amounts of 1 to 3 inches are possible, highest
across north/northeast NC. Stay tune.
Saturday: Any lingering snow across the NE coastal plain will exit
shortly after daybreak. Expect cold and blustery conditions in the
wake of the deepening coastal low lifting up the northern Atlantic
coast with another shot of cP air into the SE US. Clouds should
scattered out with sunshine returning from west to east during the
late morning and into the afternoon. Highs ranging from lower 30s NW
to upper 30s/near 40 SE. Very cold Saturday night, especially in
areas of solid snow cover. Lows ranging from lower teens north to
upper teens south.
Sunday through Tuesday: A clipper-style diving through the mid-
Atlantic region may produce some cloudiness on Thursday. Otherwise,
mid/upper levels heights will rebound early next week. After another
chilly day on Sunday, temps will quickly moderate to above normal
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 712 PM Tuesday...
Through 00Z Thursday: VFR conditions are currently found across all
of central NC, and are expected to remain that way through at least
08Z overnight. In the meantime, a cold front is moving across the
region ATTM, so we`ll see current light and variable winds become NW
10-15 kt between 00Z and 04Z...becoming NE after 04Z. When that
happens, a layer of MVFR clouds may develop and move south across
portions of central NC, with RDU/FAY/RWI most likely seeing these
clouds. Then look for any MVFR conditions to lift to VFR by 14Z
Wednesday, then remaining VFR through the rest of the TAF period.
Outlook: VFR conditions are expected to dominate Wednesday afternoon
through Thursday. An approaching storm system on Friday night into
Saturday could bring sub-VFR conditions in potential wintry
precipitation. VFR conditions are expected to return Sunday.