Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/23/22
Area Forecast Discussion
National Weather Service Charleston SC
1026 PM EST Tue Feb 22 2022
Atlantic high pressure will prevail through late week, before a
cold front passes through Friday night. The cold front could
stall offshore through the weekend. High pressure will return
early next week.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
IR satellite images late this evening indicated clear conditions
across the forecast area. Given the clear sky and light winds,
temperatures are on pace to fall into the upper 50s by daybreak
Wednesday. The primary forecast challenge will be with the
placement and timing of potential sea fog tonight. Latest runs
of the HRRR is consistent with earlier runs, showing sea fog
developing over the nearshore GA waters after midnight. SREF
probabilities of vis <=3 miles increase across the SC/GA
nearshore waters during the pre-dawn hours. Based on the model
trends, I will increase the mention of fog to indicate areas of
fog within 20 nm off the GA and lower SC coast late tonight. Fog
will struggle to develop over land given light and steady sfc
winds. However, it is possible that rounds of sea fog may spread
across the coastal areas. The fog could become more widespread
and the need for Dense Fog Advisories can`t be ruled out.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Atlantic high pressure will continue to extend into the area on
Wednesday, although a weak cold front will approach late in the
day. The front could stall near or just north of the area
before lifting back north later in the period. A weakening
shortwave will bring the next cold front towards the area on
Friday. Lack of significant forcing will maintain a dry forecast
throughout. Perhaps the most notable aspect of the forecast is
the stretch of unseasonably warm temperatures. Most locations
away from the cooler coastline will peak in the 80-85 degree
range each day. Overnight temperatures will also be quite mild
with lows generally in the upper 50s to around 60. In addition,
reduced visibilities in fog will be possible each night into
early morning, especially closer the coast where sea fog could
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A cold front will push through the area Friday night and likely
stall offshore and to the south through much of the weekend. An
upper disturbance will move through the region on Sunday which
could support isolated to scattered showers. Dry high pressure
is then expected to return for early next week. Temperatures
will gradually cool through the period.
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Prior to the 0Z TAFs, satellite, obs, and webcam at KJZI showed
some stratocu with MVFR bases near the terminal. Based on
satellite trends, these clouds should drift away from JZI early
this evening. KCHS and KSAV are forecast to remain VFR through
this evening into the late night hours. During the pre-dawn
hours into the early daylight hours Wednesday morning, forecast
soundings indicate that an inversion will develop between 1.5-2
kft. Moisture below the inversion could create a period of
restrictive ceilings, highlighted in the TAFs with a TEMPO from
10-14Z. High resolution guidance indicates that sea fog will
likely expand late tonight into Wednesday night, expected to
generally remain over the waters. Conditions should become
completely VFR after 14Z with steady SW winds.
Extended Aviation Outlook: Flight restrictions possible in
fog/low clouds each night and early morning through late week.
Tonight: Southerly flow will prevail across the local waters
with wind speeds generally topping out around 10 knots. Seas
should average 2-4 feet, highest in the outer GA waters. The
main forecast challenge will be the potential for sea fog to
develop. Current model guidance favors fog developing as early
as the early morning hours along the GA coast and then spreading
north through sunrise and thereafter. There is still quite a
bit of uncertainty regarding the timing, coverage, and intensity
of the fog so the forecast only mentions patchy fog for now.
Dense Fog Advisories could be needed late tonight and we will
continue to highlight this in the Hazardous Weather Outlook.
Wednesday through Sunday: South to southwest winds will prevail
through late week. Speeds will average 15 knots or less,
although the Charleston county waters could peak in the 15-20 kt
range Friday afternoon ahead of a cold front. Seas will be 2-5
feet. The front will cross the area Friday night and winds will
flip around to the northeast for at least the first half of the
weekend. At this point, conditions look to stay below Small
Craft Advisory criteria.
Sea Fog: Conditions will remain favorable for sea fog through
Friday. Fog could become dense at times, and Dense Fog
Advisories could be needed. This potential remains highlighted
in the Hazardous Weather Outlook.
STATION RECORD HIGH TEMPERATURE
RECORDS FOR 02-23
KCHS 82 2018
KSAV 84 2012
KCXM 78 1980
RECORDS FOR 02-24
KCHS 83 2018
KSAV 86 2012
KCXM 81 1930
RECORDS FOR 02-25
KCHS 86 2018
KSAV 87 2018
KCXM 80 1930
Area Forecast Discussion
National Weather Service Gray ME
731 PM EST Tue Feb 22 2022
Warm moisture rich air will filter into the region tonight with
rain and anomalously warm temperatures for Wednesday. Canadian
high pressure will build in for Thursday with accompanied by a
notable drop in temperatures. Attention then turns to a winter
storm system coming out of the Ohio Valley which will have
potential for widespread accumulating snowfall Friday. More
seasonable temperatures and weather expected for this weekend.
.NEAR TERM /THROUGH TONIGHT/...
730 PM UPDATE...
Surface temperatures continue to be the primary point of
consternation at this time WRT ongoing freezing rain event over
the interior. The CAD is making its presence well known today
with a northeasterly to northerly wind over the interior feeding
in lower dew points... and allowing precipitation processes to
keep temperatures well below freezing in some portions of the
western Maine mountains/lakes region, but also bring
temperatures back below freezing in other areas along the
southern and eastern periphery of the afternoon`s Winter Weather
Advisory. Thus have expanded the Advisory into interior York
and Sagadahoc, where onshore flow will take longer to work in
warmer temperatures. Road temperatures aren`t particularly
favorable in these marginal areas however elevated surfaces
still stand a good chance of ice accretion. Latest hires
guidance (mainly the HRRR grasps onto the CAD sufficiently)
still indicates this threat will wane over the entire region by
the 06Z target end time of the product... but will closely
monitor surface T trends in case an extension is needed.
Icy night for some, rain for most tonight. Winds become gusty
tonight, shifting for Wednesday as low pressure pulls into the
Temperatures across the region have warmed well since
a cool push of air last night. This has resulted in max temps
in the upper 30s to around 40 for much of southern and central
NH as well as coastal ME. With these above freezing temps
invading southern portions of the Winter Weather Adv, have
chosen to cancel it for interior York Co ME and Belknap/Grafton
Counties in NH. Do want to mention that some locations in these
counties could have been sheltered from the warmer air, thus a
few slick spots could develop on the front end of precip onset
Temperatures across the interior, sheltered by terrain, are
still well below freezing, with NAM, ECMWF, and GFS Tw aloft
indicating a quick invasion of warm air. This sets up a fairly
good environment for freezing rain this afternoon and evening
for the remaining WWY area. Have increased amts the most across
Somerset Co where up to a third of an inch of ice may be
possible at the extreme. Limiting factors may be precip rate,
and advancing warm air. Rainfall rates, focused between 7pm and
midnight, may be such that it does not have time to freeze and
cling before washing away on surfaces. Warm air mixing from
aloft as well as advancing from the south at the sfc should
overcome the remaining temps in the 20s after midnight, tapering
to rain showers.
Light NNE winds will increase rapidly from the S this evening
and overnight. This will be felt the most in the mtns and along
the Penobscot Bay region. Issued a Wind Adv for this area for
southerly gust potential up to 50 mph late tonight. While an
inversion should keep these stronger winds at bay for much of
the coast, this protection weakens along the Midcoast. This with
the mod to potentially brief heavy rain rates tonight could mix
these LLJ winds down.
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
A broad warm sector envelops the CWA Wednesday morning, with
temperatures soaring near rec highs. 60s move into southern NH
and up coastal ME.
It will also be quite breezy Wednesday as mid to low level winds
dip in heights and sfc mixing reaches up to about 900mb. While
showers will have tapered through the morning hours, any
additional clearing could enhance how much of these winds carry
to the sfc. This would be more widespread wind gusts than Tues
night, up to 30mph or more possible.
With the bulk of the day dry and windy, believe most surfaces
should dry out ahead of crashing temperatures Wed night. Winds
shift NW, with CAA wiping across the CWA. Lows fall into the mid
teens for a bulk of the region, with lows around 20 for southern
NH. The large temp swing combined with precipitation will have
some hydro impacts, or the potential, see Hydrology section.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Confluent flow over New England will keep subsidence and associated
high pressure with quiet weather on Thursday. The main forecast
challenge will be with the track and subsequent snowfall amounts
with a winter storm Thursday night through Friday night. Once again
we will see an impressive warm conveyor with deep moisture with a
potent 25H jet enhancing lift from the the Ohio Valley. The system
will fill/weaken somewhat before giving way to a new area of
surface pressure/cyclogensis off the southern New England coast
late Friday. Some differences with the upper and surface
patterns with this system, but overall looking at the H850 jet
seems to keep the system centered mainly south of the forecast
area, with the GFS the northernmost/wettest model. The anomalous
moisture combined with some modest QG forcing from the strong
upper level jet streak should yield widespread qpf from 0.5-1"
in southern half of the CWA, somewhat lesser amounts north. Snow
growth region is cold so looking at large flakes and higher
snow ratios, especially in interior Maine/N NH. The weaker lift
along the international border will result in less QPF amounts,
but the snow ratios will be a big factor in overall totals.
Overall models favor plowable snowfall for much of the area,
highest in southern Maine and New Hampshire. Given the timing of
the system expect a difficult morning and evening commutes. The
storm will be followed by cool and dry high pressure for the
weekend. A weak front on Sunday will bring some light snow
showers, primarily in interior mountain regions.
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
Short Term...IFR to LIFR possible tonight, improving to VFR Wed
morning. LLWS also likely at most TAF sites, greatest along the
NH/ME coast. Rain lifts through the area tonight, with fog
possible, especially where there is snow cover for interior
sites. Gusty winds S winds tonight, shifting W Wednesday, and
then NW Wednesday night.
Long Term...High pressure will favor fair conditions with VFR
Thursday. Widespread restrictions and wintry mix developing late
Thursday night and continuing into Friday.
Short Term...Southerly Gale conditions tonight, slackening and
shifting W Wednesday with SCA conditions continuing. Wave
heights increase 6 to 12 ft tonight, and become 4 to 8 ft Wed
afternoon. SCA conditions diminish towards Thurs morning.
Long Term...Looking at small craft conditions on Friday with the
low pressure system just south of the forecast area. This system
will support waves Strong NE/N winds 20-25 kts, and then NW
Saturday behind the cold front. Seas will at least briefly
reach 6+ ft over the outer central waters during the event.
Flood watch posted for the NW as rain increases in coverage
across the area later today/tonight, and QPF and snow melt
could combine to make some minor flooding. Recent warm ups have
helped rot some river ice, so there is a risk for ice jam
flooding primarily in smaller rivers and tributaries. The main
stem rivers have ice 9" or thicker, which should limit break up
potential given only modest river rises. Looking at impressive
high temperatures on Wednesday which will continue the
melting/runoff well into Wednesday night. This will keep a
threat for ice jam related flooding ongoing even once the rain
ME...Flood Watch from 1 AM EST Wednesday through Thursday morning
Winter Weather Advisory until 1 AM EST Wednesday for
Wind Advisory until 6 AM EST Wednesday for MEZ027-028.
NH...Flood Watch from 1 AM EST Wednesday through Thursday morning
Winter Weather Advisory until 1 AM EST Wednesday for NHZ001-
MARINE...Gale Warning until 7 AM EST Wednesday for ANZ150>154.
Area Forecast Discussion
National Weather Service New Orleans LA
829 PM CST Tue Feb 22 2022
Primary focus for this evening will be for ongoing fog production
across coastal marine areas and how far this will spread/build
down inland through the overnight hours and into the morning on
Wednesday. Looking over the latest 01Z NBM <1mi VIS probabilities
hits the greatest chances over just about all of coastal MS, where
obs are already slowly coming down right along the coast. GOES-16
Night Fog [11.2-3.9um] shows the thickest low clouds starting out
from Hancock east to Jackson, with a slight haze of light fog for
all surrounding nearshore marine zones. With light southerly
winds tonight and slightly higher observed dewpoints over SSTs in
the upper 50`s to low to mid 60`s, conditions will be much better
for fog production and maintenance. Looking like fog will become
more dense for nearshore coastal waters earlier on later tonight,
then spreading inland. Only lower confidence location of the
current Dense Fog Advisory is upwards into the Atchafalaya Basin
just how far north fog can form, spread and maintain, but feeling
good about the current area for now.
Otherwise, it will be primarily dry tonight. Latest 00Z HRRR hints
at some light isolated showers/drizzle east of I-55 including the
MS coast, but not entirely seeing support other than subtle 295 to
300k isentropic ascent at work, and perhaps some localized sfc
convergence. Additionally, we`ll see the cold front from our
northwest approach NW parts of the CWA early in the morning.
For winds, loaded in the NBM with a stronger bias towards the
HRRR to account for a realistic frontal position and attendant
wind shift, likely getting into MCB around early to mid-morning.
Something to note, where the front ends up (likely somewhere near
BTR to Franklinton line) will determine how far post-frontal CAA
can build in, which could keep temperatures a lot cooler in this
area today underneath thicker cloud cover. On the other side of
the front in the warm sector, short-range guidance hints at skies
eventually clearing out to mainly partly cloudy slowly into the
late morning and afternoon. This may lead to a slow diurnal
curve/warm up in temperatures in the morning, but may still warm
up fast in the afternoon if sunshine can become more widespread.
Played it with a blend of the 50th/75th percentile areawide south
of the front, but nudged a cooler 25th/50th percentile blend for
Additionally, just enough sfc frontogenetics combined with
building instability in the PBL to 800mb layer (below the same
subsidence inversion locked in place) may likely get some
scattered showers going, with better chances closer to the frontal
boundary mid/late morning through all afternoon. NBM hourly PoPs
reflect this well as short-range guidance is in good agreement
over this idea. Later in the evening and into tonight, the front
will remain stationary but slowly start to retreat back north.
Should the front remain locked up longer than anticipated,
continued frontogenetic ascent in the low-levels may maintain
scattered showers for northern areas even into the early overnight
hours before midnight. KLG
.AVIATION (00Z TAF DISCUSSION)...
Few patchy low clouds this evening will persist for the next few
hours with primarily VFR to a few areas of MVFR. By 03 to 06Z,
marine fog will likely begin to build inland across coastal areas
reaching coastal TAF sites first, with IFR or lower flight
categories expected to begin in this time frame (intermittent CIGS
in the VV003 to VV002 range). More fog will likely build in north
to around the I-10/12 corridor from BTR to HDC/ASD corridor
beyond 06Z into daybreak. Given the atmospheric conditions
expected, areas of dense fog may persist beyond daybreak for
coastal TAF sites with impacts expected to continue, with some
slow improvement possible late morning to around noon. Otherwise,
light showers on radar this evening will continue to dissipate,
with another round of scattered light showers at times mainly
during the afternoon on Thursday with no additional impacts
.PREV DISCUSSION... /issued 420 PM CST Tue Feb 22 2022/
SHORT TERM...As we watched radar and satellite today it looked
much like a late spring or even summer day with scattered to
numerous popcorn like showers developing. Rather decent cloud
cover and even sprinkles earlier kept the area from warming fast
this morning along with keeping the afternoon highs from quite
reaching the values initially expected.
The next 3 days will be difficult from a forecast standpoint because
that will have a lot to do with the location of a cold front that is
expected to enter the CWA during the early morning hours. What are
the concerns about this? First and the greatest impact is fog
tonight and probably again tomorrow night. Second is temperatures,
there will be a rather decent temperature gradient depending what
side of the front you are on. Temperatures will also be impacted by
rain much like it has been today.
So first fog concerns. Like the previous forecaster mentioned very
rich moisture with dewpoints in the 70s has moved over much cooler
shelf waters. The difference is as much as 10-15 degrees (maybe even
20 in isolated areas) and as soon as the sun goes down there is a
good chance of fog developing over the coastal waters right around
the coast but what about the land areas? Initially it looks like
LL winds would be too strong leading to more of a thick stratus
deck developing but winds are expected to slowly decrease
overnight. As this happens there is a good chance that the stratus
deck will slowly drop towards the sfc and for areas south of the
I 10/12 corridor and especially coastal MS and coastal SELA fog
could begin to develop as early as late this evening. Coastal
zones have the greatest threat as marine fog could also advect in
with a weak southerly wind along the coast. Looking at forecast
soundings near GPT and MSY it appears that the stratus deck
expected could drop quickly in these areas with dense fog
impacting these locations before midnight. One last positive for
fog is we have a weak cold front trying to slide down into the
region before sunrise and generally these slow moving cold front
will have moisture pool ahead of it this will also aid in the
production of fog tonight. Again the biggest concern over the land
areas is stratus not dropping to the sfc due to strong LL winds
however, the threat of moderate to dense fog is pretty good. With
that we have issued a dense fog for a good chunk of the region
We just mentioned the cold front approaching and that will be a
problem through the short term forecast. The ridge over the
southwestern Gulf will remain strong with deep west-southwest flow
aloft and this will provide no real push to get the front through
and it will likely stall over the area early tomorrow. This will
help provide a little bit of a focus to get scattered showers across
portions of the CWA tomorrow. As a sfc low starts to take shape near
the TX/OK panhandle it will likely cause the stalled front to lift
back to the north as a warm front. That will be short lived though
as a sfc low develop over southern TX will lift northeast with a s/w
moving through the plains and into the Mid MS Valley. This low will
track into KY and WV and it will finally drive a cold front into the
Gulf but it will be slow. Additional light rain is possible with
LONG TERM...Quite a bit of uncertainty in the extended portion of
the forecast. Ensemble means are in good agreement with the pattern
setup this weekend and early next week but b/c of this there could
be rather large shifts with respect to temperatures and frontal
locations. Confidence is rather low in the forecast so we will stick
to the NBM at this point but an honest opinion it along with most of
the guidance appear to be a little on the high side respect to
morning lows a few days.
This weekend and into next week it is all about the cold front.
Model spreads in the temperatures, especially the NBM is rather
large. That said all of the deterministic guidance is on the lower
end and most of the ensemble guidance is on the lower end as well.
Honestly with the setup though we would like to lean a little higher
with the temps but given everything is lower we have a hard time
finding the confidence to make that change right now. This starts as
early as Saturday morning with forecast lows in the mid 40s to mid
50s but given the slow push of the front and the likelihood of
overrunning moisture bringing clouds and even possibly rain, morning
lows should really struggle to get that low. If the cold front has a
cleaner push then the morning low forecast is fine. There is another
re-enforcing cold Sunday and that should finally drive through
completely with northwest flow finally in place Sunday night this
will likely provide cool yet nice conditions across the region for
Lundi and Mardi Gras. /CAB/
MARINE...Biggest concern for the marine areas will be fog. Very
rich moisture with dewpoints about 10-15 degrees or even more
warmer than the SST should easily allow for the production of
Marine fog quickly this evening. Winds will relax as well
overnight but could help to advect some of the fog inland. Cold
front will stall north of the coastal waters tomorrow but a cold
front should finally drop into the Gulf Saturday and a strong one
on Sunday. /CAB/
.PRELIMINARY POINT TEMPS/POPS...
MCB 65 81 62 81 / 40 40 20 30
BTR 66 83 63 82 / 10 40 20 30
ASD 65 81 60 79 / 10 20 10 20
MSY 67 81 65 79 / 10 20 20 20
GPT 63 76 60 74 / 10 10 10 10
PQL 64 79 60 74 / 10 10 0 10
LA...Dense Fog Advisory until 10 AM CST Wednesday for LAZ046>050-
GM...Dense Fog Advisory until 10 AM CST Wednesday for GMZ530-532-534-
MS...Dense Fog Advisory until 10 AM CST Wednesday for MSZ080>082.
GM...Dense Fog Advisory until 10 AM CST Wednesday for GMZ532-534-536-
AREA FORECAST DISCUSSION
National Weather Service Morristown TN
926 PM EST Tue Feb 22 2022
The front is still off to our west, but showers and some thunder
are moving northeast with the flow across our area and the overall
motion of this band of precip has slowed to a crawl allowing
training which is bringing heavy rainfall especially southern and
western areas. The Flood Watch still looks to be warranted given
this set up. The shear is strong, but limited instability has led
to convective cells weakening as they move into our area. This
trend should continue, but we will still need to be alert for any
stronger storm and brief tornado spin ups mainly Southern Plateau
and adjacent areas.
Will lower most temps a bit with this update given many obs are
approaching lows already. Will also bump winds up a bit over the
00Z TAF DISCUSSION.
Will see rain and perhaps some rumbles of thunder especially CHA
moving across the area tonight. Conditions will become mainly
MVFR/IFR as the precipitation moves through, with some improvement
during the day Wed although MVFR cigs look likely to linger for
much of the day. LLWS looks borderline early tonight but the best
chance looks to be at CHA, so will include it for a few hours
/ISSUED 311 PM EST Tue Feb 22 2022/
SHORT TERM...(Tonight and Wednesday)...
1. Focus of heavy rainfall tonight along a mesoscale boundary for
the central East Tennessee valley and northern Cumberland Plateau.
One to three inches expected with locally higher amounts.
2. Drier Wednesday with clouds hanging around for most areas.
Current radar imagery shows a line of rain extending from SW VA
across the northern Cumberland Plateau and southwestward through
Middle TN. This will provide an mesoscale focus for additional
rainfall through the evening and overnight hours. Ahead of the
cold front tonight, southwest winds increase with the RAP showing
a focus of low-level boundary layer convergence across the I-40
corridor through Middle TN and into East TN. The strongest low-
level convergence will likely be later tonight between 05z and 09z
across the northern Cumberland Plateau and central East Tennessee
Valley near Knoxville. The RAP shows PW values around 1.5 to 1.6
inch during this time period with low values of skinny MUCAPE
around 200 J/Kg. This will be supportive of heavy rainfall rates
and potential training as convection develops with storm layer
steering flow nearly parallel to this mesoscale boundary. HREF
guidance continues to indicate the potential for 1 to 3 inches of
rain with locally higher amounts, and with morning rainfall today,
6-hr FFG are now around 2 to 2.5 inches or less because of the
wetter antecedent conditions. With the anomalously high moisture
and being in the warm sector, temperatures remain well above
The cold front should be mostly southeast of the area by 15z
Wednesday with slightly drier air arriving behind the front.
Expect to continue with mostly cloud sky conditions, especially
across the valley and eastward around the mountains and foothills.
Max temperatures remain slightly above normal with upper ridging
and the bulk of cold air remaining to our northwest as the cold
front stalls out just to our south.
LONG TERM...(Wednesday night through Monday night)...
1. Another system will impact the region Wednesday night through
Friday morning with locations north of I-40/I-81 expected to see
heavier totals of an additional 1" to 2" or more of rainfall.
2. Saturday is dry and cooler before another system is expected
Saturday night through Sunday. Confidence remains limited, but an
area-wide rain/snow mix is possible. Snow accumulation (if any) will
likely be confined to the higher elevations of the Northern
Cumberland Plateau, SW Virginia and the East Tennessee Mountains.
Wednesday Night through Friday
In the upper levels, a ridge will be over the Southeast with nearly
zonal flow over the region becoming more southwesterly Thursday
night. At the surface, a boundary will develop near the
Tennessee/Kentucky state line on Wednesday night. This boundary will
slowly lift north on Thursday. Thursday night this system will get
better organized with a more discernible low and cold front. The
cold front will move through the region late Thursday night into
Friday morning. The first round of rain will be along the
stationary/warm front Wednesday night and Thursday. A steadier rain
and therefore higher rain totals are expected along and north of I-
40/I-81 with 1 to 2 inches total forecast there in addition to rain
received earlier this week. The second round of rain will be more
widespread as the cold front moves through late Thursday night into
Friday morning. Minor flooding issues may occur late this workweek
mainly north of I-40/I-81. Ponding of water on roadways and ponding
in low lying areas are the biggest concerns. Conditions do not look
favorable for strong or severe storms since instability will be low.
A few rumbles of thunder cannot be ruled out.
Saturday will be dry and cooler with highs in the upper 40s and near
50. The next system is expected Saturday night into Sunday.
Temperatures will be cool enough Saturday night to get a rain/snow
mix in many locations. Confidence remains limited, but this does not
look like a big event at this time. Snow accumulation (if any) will
likely be confined to the higher elevations of the Northern
Cumberland Plateau, SW Virginia and the East Tennessee Mountains.
Monday and Monday night will be dry and cool with highs in the upper
40s and lower 50s.
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 56 66 50 72 52 / 90 60 40 30 60
Knoxville McGhee Tyson Airport, TN 54 62 47 67 52 / 100 60 60 60 50
Oak Ridge, TN 54 61 45 64 50 / 100 50 60 60 60
Tri Cities Airport, TN 52 61 45 61 50 / 100 60 60 80 40
TN...Flood Watch until 7 AM EST /6 AM CST/ Wednesday for Anderson-
Bledsoe-Blount Smoky Mountains-Bradley-Campbell-Claiborne-
McMinn-Meigs-Morgan-Northwest Blount-Northwest Monroe-Rhea-
Roane-Scott TN-Sequatchie-Southeast Monroe-Union-West Polk.
VA...Flood Watch until 7 AM EST Wednesday for Lee-Wise.
Area Forecast Discussion
National Weather Service San Diego CA
113 PM PST Tue Feb 22 2022
A cold winter storm has arrived in SoCal, which will continue to
bring rain and snow showers, gusty west winds, and cold
temperatures through the middle of the week. Just as quickly as
the trough will dig south through tomorrow, high pressure over the
Pacific will expand as the storm departs to the east. Though dry
weather can be expected starting Thursday, Thursday and Friday
mornings will be quite cold for areas west of the mountains
especially. A warming trend will begin Thursday as well, where
temperatures are expected to reach near average by the weekend.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
.SHORT TERM...(Today through Wednesday Night)...
A large trough will continue to dig south into Southern
California today and Wednesday. This has led to the chilly
temperatures we are seeing this afternoon with many areas
currently with widespread 50s for the coastal valleys and 30s/40s
for our mountain areas. Gusty winds have accompanied this system
where gusts over 50 MPH will continue across parts of the
mountains and deserts through tonight. Coastal and valley regions
west of the mountains will continue to see west winds gusting near
35 MPH at times. Hi-res model guidance points to less wind by
Wednesday but still gusty across mountains and desert regions with
widespread gusts 30-40+ MPH possible.
Scattered showers this afternoon will increase in coverage as the
trough moves south and east over SoCal this evening. Heaviest
precipitation will be expected area wide tonight into early
Wednesday morning, diminishing from north to south on Wednesday.
Rain totals will be greatest over San Diego County per latest WPC,
local WRF, and HRRR guidance. Most areas west of the mountains in
SD County will see one half to locally over one inch of rain,
which OC/IE will receive near one quarter. Deserts may also see a
bit of rain as well! Orographic lift will be most prominent across
RIV and SD Counties favoring high precip totals, including snow.
These areas will see widespread snow totals of 8-12 inches in
higher terrain, locally one to two feet in some spots.
.LONG TERM...(Thursday through Early Next Week)...
High pressure will build off the Pacific on Thursday and expand
into California slowly into the weekend. Though we will see a
gradual warming trend, low temperatures will be quite cold on
Thursday and Friday mornings, especially in valleys west of the
mountains. ECMWF Extreme Forecast Index along with NBM 10th
percentile and GFS MOS point to single digits widespread mid 20s
to low 30s for the valleys of SD County into the Inland Empire by
Thursday morning, which may lead to freeze conditions. Friday
morning will be slightly warmer, but we still may see ares dip
below the freezing mark. As the high moves over the southwest,
this will lead to more dry weather by Thursday into the weekend.
High temperatures will return to average readings by this
weekend. A weak shortwave may brush the region by early next week,
which would provide cooler temperatures and greater onshore flow.
222045Z...BKN-OVC030-040 with tops to 15000 feet with SHRA through
24Z, lowering to BKN-OVC020-030 from 00Z-14Z with widespread
SHRA/TSRA over/west of the mountains. -SHRA extending into deserts.
CIGS 2000 feet and vis 1-3 SM in heaviest showers.
Mountains: Obscured in clouds/fog/pcpn. Mountains experiencing near
blizzard conditions at times from 00Z-14Z with 30-50 kt winds and
heavy snow. Snow level lowering to 2000 feet overnight.
Deserts: West to northwest winds through the passes and down the
desert mountain slopes with gusts 30-50 kt. Strong up/downdrafts
over/east of the mountains with rotors and LLWS vcnty KPSP. Reduced
visibility to 1-4 miles in BLDU at times.
SMALL CRAFT ADVISORY THROUGH 10 PM WEDNESDAY for northwest winds of
15-30 kt and steep choppy seas from a large short-period swell.
Scattered showers and thunderstorms through Wednesday morning.
No marine hazards are expected Wednesday night through Saturday.
Elevated surf of 3-6 feet from a short-period northwest wind swell
today through Wednesday. High rip current risk. Ocean water
temperatures from 57-61 degrees.
Mostly light showers will continue this afternoon with the
greatest coverage along and near the coastal slopes of the
mountains with widespread showers in the mountains. Widespread
showers will develop near sunset over the region. Some showers
could produce small hail or graupel. There is also a slight chance
of thunderstorms for late this afternoon into early Wednesday
morning. Snow levels around 4500 feet this afternoon will fall to
2000 to 2500 feet for late tonight into Wednesday morning.
Showers will continue on Wednesday with greatest coverage in the
mountains and across San Diego County. Showers will end from the
northwest late Wednesday afternoon and Wednesday night.
For Orange and southwestern San Bernardino Counties through
Wednesday, rainfall and liquid equivalent above the snow level is
expected to range from one-tenth to one-quarter inch near the
coast to one-half to one inch in the mountains with locally
greater amounts with mostly one-tenth inch or less in the high
desert. Light snowfall is possible down to around 2000 feet with
4 to 6 inches from 4000 to 6000 feet and 6 to 12 inches above
6000 feet with locally greater amounts on higher peaks.
For San Diego and western Riverside Counties through Wednesday,
rainfall and liquid equivalent above the snow level is expected to
range from around one-half inch near the coast to 1 to 2 inches
in the mountains with mostly one-tenth to locally one-quarter
inch in the lower deserts. A snow level around 4500 feet will
lower to around 2500 feet for late tonight into Wednesday morning.
Light snowfall is possible down to around 2500 feet with 6 to 12
inches above 4000 feet with local amounts of one to two feet on
the higher peaks.
Skywarn activation is requested.
CA...High Wind Warning until 4 PM PST this afternoon for Riverside
County Mountains-San Diego County Mountains.
Winter Storm Warning from 4 PM this afternoon to 6 PM PST
Wednesday for Riverside County Mountains-San Diego County
High Wind Warning until 9 PM PST this evening for Coachella
Valley-San Diego County Deserts-San Gorgonio Pass Near
Winter Weather Advisory from 4 PM this afternoon to 6 AM PST
Wednesday for Apple and Lucerne Valleys.
Wind Advisory until 4 PM PST this afternoon for Apple and
Lucerne Valleys-San Bernardino County Mountains.
Freeze Watch from Wednesday evening through Thursday morning for
San Diego County Valleys.
Wind Advisory until midnight PST tonight for San Diego County
Coastal Areas-San Diego County Valleys.
Winter Storm Warning from 4 PM this afternoon to noon PST
Wednesday for San Bernardino County Mountains.
Winter Weather Advisory from 4 PM this afternoon to noon PST
Wednesday for Santa Ana Mountains and Foothills.
Hard Freeze Watch from Wednesday evening through Thursday
morning for San Bernardino and Riverside County Valleys-The
Wind Advisory until 6 PM PST this evening for Orange County
Coastal Areas-Orange County Inland Areas-San Bernardino and
Riverside County Valleys-The Inland Empire.
PZ...Small Craft Advisory until 10 PM PST Wednesday for Coastal
Waters from San Mateo Point to the Mexican Border and out
to 30 nm-Waters from San Mateo point to the Mexican Border
Extending 30 to 60 nm out including San Clemente Island.
Full Forecast Discussion:
Temperatures have struggled to warm even a few degrees today due to
continued cold air advection behind yesterday`s strong front. The
tight pressure gradient currently evident on surface maps is keeping
winds breezy across KS as low pressure exists east of the area and a
1045 mb surface high resides in Montana. The combination of very
cold ambient temperatures and continued breezy north winds tonight
will create dangerous wind chill readings tonight and Wednesday
morning. Thus, we have issued a Wind Chill Advisory from 8 PM this
evening until 11 AM Wednesday where wind chills are expected to drop
to -15F or lower. After sunrise, temperatures should increase more
than they did today, however, we went with the 25th percentile of
model guidance for afternoon highs, which would keep temps
generally in the low 20s.
The next storm system to watch is a mid-level system set to move out
of the Four Corners region on Thursday. A cold air mass will remain
in place so if precipitation occurs, it will be of the wintry
variety, largely in the form of snow. Deterministic models are
still not in great agreement with the amount of saturation through
the DGZ on Thursday, and the amount of ascent that will occur as
the system advances toward the area. SREF plumes show decent
agreement in lower snow totals with an average between 0.5" and
1.0" of snow in Topeka. GEFS plumes average a little higher,
around 2.0" of snow in Topeka. Until confidence increases, we are
going with a uniform 0.5" to 1.0" of snow accumulation area-wide
on Thursday. South of I-35, freezing drizzle also looks possible
for a few hours where conditions look drier in the DGZ.
Following some light snow or freezing drizzle on Thursday, temperatures
will undergo a noticeable warming trend through this upcoming
weekend with temperatures back in the 50`s by Sunday afternoon.
Another mid-level trough will move over the area this weekend but
with minimal impacts as it is currently expected to come through
.AVIATION...(For the 00Z TAFS through 00Z Thursday)
Issued at 453 PM CST Tue Feb 22 2022
Cold and dry high pressure will continue to build in from the
north tonight. The RAP and GFS show some high RH in low levels
implying some stratus persisting overnight. However satellite
shows clouds upstream to be cumuliform. So think these should fall
apart with the loss of daylight. But will keep an eye on this
since forecast soundings show such cold temps in the lower
troposphere that it wouldn`t take much to saturate. Otherwise VFR
conditions should persist.
Wind Chill Advisory until 11 AM CST Wednesday for KSZ008>012-