Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/08/21
Area Forecast Discussion
National Weather Service La Crosse WI
546 PM CST Thu Jan 7 2021
.SHORT TERM...(This evening through Tonight)
Issued at 211 PM CST Thu Jan 7 2021
Forecast concerns in the short term will continue to be the
potential for dense fog, timing, and extent.
The dense fog this morning was more patchy in our WI counties, but
had spread west into MN/IA with LIFR conditions and 1/4 to 1/2sm
visibilities at RST, TOB, CCY, OLX at times between 6am and 9am.
Water vapor satellite imagery, 500mb heights and observations had
the closed low over Mississippi with the trough extending northwest
through Arkansas and Missouri toward southwest MN. This morning`s
MPX sounding had a shallow moist layer to around 600ft with the
inversion around 1700ft. The latest surface analysis showed that
the 1029mb surface high pressure center over WI was still over WI,
but a little stronger at 1035mb. During the morning, visibilities
had dropped over much of central MN in the light southeast flow.
Through Friday morning, the RAP forecasts the surface high to move
westward and cover much of Minnesota and extend into WI and IA at
around 1030mb. Relative humidity values remain high overnight from
95 to 100% with low dewpoint depressions. The forecast soundings
continue to show low mixing in the lowest 2-3Kft and the 900mb .
winds are quite light. The HREF probabilities have the best signal
for visibilities < 1 mi just to the west of our county warning area
(CWA), however ceiling probabilities of <1000ft are still pretty
high across the CWA. The RAP signal covers more of southeast MN
compared to the others. For now in coordination with offices to our
northwest, do mention dense fog in our southeast MN zones, however
the dense fog advisory is currently where the confidence is higher
for widespread dense fog more into central and western MN. Other
fog favored locations will also experience the fog due to the
favorable conditions.
.LONG TERM...(Friday through Thursday)
Issued at 211 PM CST Thu Jan 7 2021
Not much has changed in the extended recently, as things still look
fairly quiet and mild into the beginning of next week.
The region remains under the influence of high pressure anchored
just to our west Friday through the weekend, which will help keep
things dry. We will, however, likely have to contend with the
same low cloud/fog challenges as the last several days thanks to
the persistent and strong low-level temperature inversion keeping
moisture trapped beneath it. It`s possible this weakens some on
Sunday as a shortwave drops into the area, but this might not be
enough to make an appreciable difference given lackluster
temperature advection in the low-levels. Ensemble guidance really
highlights the overall dryness of this stretch well, with none of
the 30 07.12Z GEFS and 50 07.00Z EPS members even exceeding 0.05"
until Monday night into Tuesday at the earliest, when a shortwave
drops out of southern Canada. Given saturation issues,
precipitation is not a given with this system, either, and we may
have to wait until late week when larger troughing tries to move
in for a better shot at precipitation. Temperatures look to stay
mild with highs in the 20s and 30s through the weekend and likely
into the new week as well.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 540 PM CST Thu Jan 7 2021
Fog and low stratus forecast challenges continue again tonight
into Friday. Pretty high confidence in MVFR ceilings persisting
at LSE through the period with some MVFR visibility issues later
tonight through Friday morning. RST poses more of a forecast
challenge, as it looks to sit right on the edge of more widespread
LIFR conditions just to the north and west, and guidance is not
in good agreement for tonight. Expecting a drop from current MVFR
cigs/vsby to IFR within a few hours, with LIFR conditions very
possible late tonight. Will be monitoring trends, but did not have
enough confidence at this time to remove LIFR conditions. Should
see improvement to MVFR Friday afternoon. Northerly winds will
remain under 10 knots through the period.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Zapotocny
LONG TERM...Lee
AVIATION...Kurz
Area Forecast Discussion
National Weather Service Des Moines IA
540 PM CST Thu Jan 7 2021
.DISCUSSION.../Tonight through Thursday/
Issued at 244 PM CST Thu Jan 7 2021
The primary weather themes will be generally dry conditions and
intermittent low cloudiness into at least early next week. Our
weather will enter a fairly dormant period with weak flow across
the MO Valley. There is a noted PV anomaly upstream along the
UT/CO border this afternoon, but it is expected to track into the
southern Plains with little fanfare keeping our forecast dry. Our
main sensible weather for the next few days will continue to be
stratus and areas of fog, with the better dense fog potential
north. Confidence is not there for an advisory at this point
however. Expect conditions similar to the past few nights with
some areas of dense fog, but not widespread enough to target a
headline as of yet.
The pattern will attempt to strengthen a bit early next week.
500mb winds will stay <= 20kts until Sunday when the SW edge of a
weak short wave drifts through the Upper MS Valley. The forecast
will remain dry however with little in the way of sufficient
moisture or lift for precip. The process looks to repeat to some
degree around Tuesday, but with similar results as the southern
stream stays more active. The GFS and ECMWF do eventually suggest
a decent short wave passage and the potential for light precip
either Wednesday or Thursday respectively as the long wave trough
finally begins to amplify. Confidence in which solution is
correct is low however, so rather than broad-brush low PoPs
through both periods the forecast remains dry until trends suggest
otherwise.
&&
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 540 PM CST Thu Jan 7 2021
Little change to overall pattern with high northeast of region
and lingering boundary layer moisture with light winds. Many sites
already MVFR with IFR northwest. Expecting cigs to drop again to
IFR/LIFR with definite MVFR br and perhaps some FG. Site most
likely to see FG would be KMCW, though uncertainty remains. HRRR
has continues to be overly aggressive in rapid lowering of cigs
and vsbys each run. Questions remain about some return to VFR
conditions east on Friday. Today high exerted enough subsidence to
remove lower cigs/fog. Similar trends in synoptic models for
tomorrow may lead to lifting cigs at KALO/KOTM and KDSM by 15z to
18z. High res continue to keep areas IFR. Will evaluate again next
package with more info for 12z by midnight shift. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Small
AVIATION...REV
Area Forecast Discussion
National Weather Service Goodland KS
443 PM MST Thu Jan 7 2021
.SHORT TERM...(This evening through Friday night)
Issued at 1259 PM MST Thu Jan 7 2021
Visible satellite shows cloud cover persisting over the eastern and
northeastern part of the CWA this afternoon. Clouds have begun to
expand in coverage from east to west across the Tri-State area over
the past several hours. The area remains under northerly flow aloft
this afternoon as a weak ridge moves into the region. Behind it, a
shortwave trough is diving south into Wyoming. High temperatures
today will range from the low to mid-40s in Eastern Colorado where
cloud cover has been significantly less today to the mid to upper
30s in much of Northwest Kansas and southwest Nebraska.
The main change to the forecast for tonight is bringing temperatures
up a little in the eastern part of the forecast area. Low-level
clouds are continue to impact the area which would limit the amount
of radiational cooling expected. Lows will range from the teens to
mid-20s across Eastern Colorado to the upper 20s around Norton and
Hill City. Patchy fog may develop after midnight, primarily in
areas along and east of Highway 83.
Friday, the shortwave trough and a closed low will slide to the
southeast, through the Tri-State area. Fog should burn off by
around mid-morning. Brought in a slight mention of PoPs from McCook
to Norton as wrap around moisture may give us a brief window for
some drizzle in the late morning to early afternoon hours.
Temperatures will be a bit warmer with highs in the 40s. Lows will
be in the teens and twenties.
.LONG TERM...(Saturday through Thursday)
Issued at 1259 PM MST Thu Jan 7 2021
The main concern for the extended forecast is the possibility for
some precipitation on Saturday. An upper trough will continue to
dive to the south with low pressure moving in, over the Texas and
Oklahoma panhandles. Precipitation chances are low but cannot be
entirely ruled out on Saturday. Rain and snow are expected to be
the primary p-type. Precipitation chances should stay limited to
Eastern Colorado and areas along and south of Highway 40.
The low will continue to move to the east through the rest of the
weekend and into the start of next week. An upper ridge will move
into the region with a gradual warming trend expected through the
end of the forecast period. High temperatures by Wednesday will
return to the 50s with dry conditions expected.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 438 PM MST Thu Jan 7 2021
KMCK will stay in low clouds through at least Friday morning, and
possibly the entire TAF period. Expect ceilings there to be mostly
MVFR, but cannot rule out a period of IFR or even LIFR during the
overnight through Friday morning time period. Visibility
reductions in fog will also be possible through Friday morning.
Forecast less certain at KGLD. Satellite imagery at 2340z shows
the lower ceilings slowly creeping westward and now in eastern
Sherman County. Based on that and the HRRR forecast, will lower
ceilings at KGLD this evening and continue through tonight, but
confidence in ceilings at KGLD is very low. Should see ceilings
lift Friday morning with light west to northwest surface winds.
Not expecting fog at KGLD for now, with slightly higher dew point
depressions and light downsloping drainage winds expected to
develop.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...AW
LONG TERM...AW
AVIATION...024
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1039 PM EST Thu Jan 7 2021
.SYNOPSIS...
A moist storm system arrives from the west tonight and will pass
east of the area Friday through Friday night. Widespread wintry
weather is expected for many locations with this system, with the
best chances and most significant accumulations over the mountains
and foothills. Canadian high pressure returns to the region over the
weekend. Another low pressure system is likely to affect the area
early next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1030 pm EST: Greenville, Spartanburg, and Cherokee Counties
have been added to the Winter Weather Advisory for light
accumulating snowfall through Friday evening. Recent RAP model runs
have trended colder quicker across the far northern Upstate and this
should lead to a slightly earlier changeover to primarily snow
across the northern portions of these counties. In addition, the
potential for snow showers as the steeper lapse rates move through
on Friday could bring light accums closer to the I-85 corridor.
Locations southeast of I-85 will still see primarily a cold rain,
but with some sleet or snow showers at times.
Otherwise, the forecast remains on track with the first
precipitation shield moving across the heart of the forecast area
late this evening. Ptypes are almost exclusively snow at this point
across the bulk of the mountains and should remain that way for much
of the duration of the event. No other hazard adjustments will be
made late this evening.
The latest WV imagery reveals the approaching upper cyclone centered
over NE AL, with strongly diffluent flow downstream over much of the
Deep South and the TN Valley. Forcing and moisture ahead of this
system will increase rapidly across our forecast area through the
nighttime hours, with precip chances ramping up quickly across the
region. A surface ridge extending from surface anticyclone over
Ontario will spill into the area through the period, resulting in
increasing low-level NE flow and gradually advecting lower wet bulb
temp air into the forecast area. With wet bulb temps are already
around freezing across much of the NC mtns, those areas will see
almost exclusively snow as the precip intensifies. The Little TN
Valley and adjacent valleys are warmer as usual, and will likely see
almost as much RA as wintry precip.
Locations east of the mountains remain more problematic and pytpes
will depend more heavily on temperature trends in the lowest 1000`
or so. While all locations east of the mtns will more than likely
start out with rain, mixed briefly with sleet, advection of the
lower wet bulb air should support a transition to snow along and
north of I-40, and in fact, precip should be more frozen than not in
those areas. Closer to the I-85 corridor, things get a lot trickier,
but with profiles trending cooler as indicated in the decision to
expand the advisory. Periods of stronger synoptic forcing will
support high precip rates at times tonight (classic "cross-hair
signature" indicated in model cross sections), and this may force
periods of a mix with or transition to SN, although how much that
would be able to accumulate is debatable. Another source of
uncertainty is the potential for a narrow band of mixed precip, most
likely sleet, but a brief period of FZRA can`t be ruled out, as the
NAM has been consistent in developing a warm nose, albeit not a
particularly strong one near the NC/SC border tonight. Since the NAM
usually does a good job in capturing these features, even when other
guidance does not, we continue to forecast a region of sleet from
the GA/SC/southern NC mtns into the Piedmont. Forecast accumulation
is minimal, but this does create another pitfall for the snow accum
forecast.
Of greater concern for areas east of the mtns, and especially the
Piedmont and I-77 corridor, will be the potential for mesoscale
banding during the daylight hours Friday, as a deformation zone
matures in response to cyclone deepening off the coast. Convection-
allowing models, especially those that are NAM-based and even the
operational NAM itself depict potential for locally high precip
rates, esp across the Piedmont from late morning into the afternoon,
possibly resulting in quickly accumulating snowfall, even in areas
outside the warning. Of course, predicting where exactly this will
(or if it will) set up is akin to predicting where a cluster of
thunderstorms will develop 24 hours in advance. Nevertheless, the
potential exists for locally intense snowfall rates tomorrow,
especially across the Piedmont.
In terms of amounts: storm totals are forecast to range from 5 to 10
inches across the NC mtns, except more in the 1-3 inch range across
the valleys of far southwest NC and over much of Rabun County GA.
Four to six inches are expected across the northern NC foothills,
where a developing stout easterly flow is expected to enhance precip
rates tonight, while 2-4 inches are generally forecast for the
northwest NC Piedmont. General 1-2 inch amounts are forecast in the
Advisory areas detailed above, although the southern part of those
zones may see little to no accum.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 130 PM EST Thursday: Northwest flow snow showers may linger
into early Saturday morning before low level moisture drys out.
Additional light accumulations are possible near the Tennessee
border. Dry high pressure will build into the region to support
sunny and cool conditions this weekend. Where a healthy snowpack
persists, diurnal melting of the snow and well below freezing
temperatures at night may allow for a lingering black ice threat.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 145 PM EST Thursday: Low confidence continued for the
extended portion of the forecast. Model guidance continues to
struggle with a possible winter storm early next week. The latest EC
has trended towards the GFS and its ensembles towards a more
suppressed, colder system. It seems guidance is struggling with how
much if any phasing of the southern northern stream jets will occur.
The forecast continues to feature mountain snow showers with
transition of rain/snow showers across the Piedmont and rain for far
southern areas late Monday into Tuesday. It appears cold and mostly
dry west/northwest flow will prevail later in the week as general
troughiness remains in place.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: The shield of more solid precipitation filled
in quickly from the southwest this evening. Anticipate lowering VFR
bases early on, quickly dropping to MVFR through the evening hours,
and becoming IFR overnight as profiles saturate. Most locations
should get locked into the IFR range, with LIFR possible at times,
for the rest of the terminal forecast period. Ptypes will be quite
the concern throughout, with sleet mixing in at all sites briefly at
onset, but with primarily rain at the Upstate sites and KCLT, and
primarily snow at KAVL and KHKY as the profiles saturate. Expect
sleet and possibly snow to mix at times through Friday morning even
for the Upstate sites and KCLT as profiles cool from the top down as
the 850 mb low center moves east. The main question mark for heavier
snow showers and rapidly lowering cigs and vis Friday will be where
the banding of precipitation sets up through the day. Anticipate
that nearly all sites will have a decent shot of at some moderate or
better snow bands in the afternoon or evening hours, with the best
chances across the NC TAF sites including KCLT. Anticipate NE winds,
gusty at times, east of the mountains, with SE flow at KAVL early
turning back to the NW.
Outlook: Some improvement in flight conditions is possible Friday
night in the wake of the storm system. Drying is expected over the
weekend. Another storm system may impact the area Monday night into
Tuesday with precipitation and associated restrictions.
Confidence Table...
03-09Z 09-15Z 15-21Z 21-00Z
KCLT High 90% Med 75% High 96% Med 79%
KGSP Med 68% High 80% High 85% Med 73%
KAVL High 85% High 93% High 86% High 83%
KHKY High 88% High 100% High 88% High 80%
KGMU Med 71% Med 76% High 86% Med 67%
KAND Med 61% Med 61% Med 66% High 83%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Winter Weather Advisory until midnight EST Friday night for
GAZ017.
Winter Storm Warning until midnight EST Friday night for
GAZ010.
NC...Winter Weather Advisory until midnight EST Friday night for
NCZ508-510.
Winter Weather Advisory until midnight EST Friday night for
NCZ068>072.
Winter Storm Warning until midnight EST Friday night for
NCZ033-035>037-048>050-052-053-056-057-059-062>065-
501>507-509.
Winter Weather Advisory below 3500 feet until midnight EST
Friday night for NCZ051-058.
Winter Storm Warning above 3500 feet until midnight EST Friday
night for NCZ051-058.
SC...Winter Weather Advisory until midnight EST Friday night for
SCZ001>003.
Winter Weather Advisory until midnight EST Friday night for
SCZ006>008.
&&
$$
SYNOPSIS...DEO
NEAR TERM...HG/JDL
SHORT TERM...Munroe
LONG TERM...Munroe
AVIATION...HG/JDL
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
941 PM EST Thu Jan 7 2021
.SYNOPSIS...
Cloudy conditions with seasonable temperatures continue into
Friday. As an upper level low passes south of the region, some
light snow and flurries will be possible along and south of the
Ohio River Thursday night into Friday morning. Dry conditions
will then return for the weekend, with some additional breaks
in the clouds expected on Saturday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
An upper level low currently centered over western Tennessee
will continue moving slowly eastward overnight. On the northern
periphery of this low, the focus for the forecast tonight has
been on the potential for snow to develop on a swath from
central to northeastern Kentucky. Presently, there are two
layers of clouds across this area -- thick stratocumulus at
around 3kft, and a mix of mid and high clouds that have
overspread much of the middle Ohio Valley. In between these two
layers, there is definitely some dry air at around 850mb, which
will be one limiting factor for snow potential. Forcing is
somewhat hard to pin down, but appears to be broad and largely
elevated, though enough to produce a semi-consistent band of
lift for several hours overnight. Most model guidance this
evening (00Z runs of various models plus earlier HRRR/RAP runs)
is in agreement on this general scenario, but not so much on
eventual snow amounts. However, there has been enough evidence
in accumulating snowfall to force a change in the forecast, with
significantly increased PoPs and the potential for up to an inch
across the /extreme southern/ portion of the ILN CWA. This
really only effects the southernmost tier of ILN counties, with
perhaps some potential for flurries or a tenth or two in the
next tier further north. Of the models, the RAP has been the
most consistent on the high end, but it may be saturating the
aforementioned dry layer too quickly.
Previous discussion >
Overcast skies continue overnight as low-levels remain
saturated. The primary feature to pay attention to will be the
progression of an upper-level low pressure system across the
southern CONUS. This will usher in some higher RH and a chance
for pcpn - primarily in the form of snow - across a large
portion of KY. Hi-res models hint at the potential for a narrow
band of heavier snow to occur in north-central KY, but this
currently appears to stay just south of our counties. However,
did slightly nudge PoPs up tonight in counties located south of
the Ohio River as the potential for snowfall exists in those
locations. While only a tenth of an inch is currently forecast
across our southern most counties, this will be something that
will be monitored through the evening and overnight hours if the
banded snowfall shifts further northward. Additionally, kept in
the potential for snow flurries across some of our southern
Ohio counties through early Friday morning - but this appears to
be non-accumulating.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Other than light snow/flurries tapering off across our far
southern counties Friday morning, expect similar conditions to
persist through this period with overcast skies and seasonable
temperatures. With split flow aloft, no major changes to the
weather pattern are occurring. Expect mainly dry conditions
across the fa through this period.
Late Friday night, 850mb flow will begin to shift more towards
the east. In turn, this will help dry out some of the middle to
lower levels and provide more breaks in the clouds as we
progress through the night. Low temps Friday night are forecast
to be a few degrees cooler than Thursday night due in part to
the thinning cloud coverage.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Split mid level flow with surface high pressure to offer dry weather
thru the weekend. Clouds look to linger into Saturday when some
partial clearing is expected.
Moisture from the southern stream could graze our extreme southeast
counties late Monday/Monday night. Have limited any pops to only a
slight chance of a snow shower over southeast.
Flow amplifies with northwest mid level flow developing by the end of
next week. Model solutions show considerable spread on the details
at this time frame. Have chance pops for rain/snow later Thursday.
Temperatures look to be near normal with highs generally in the 30s
and lows in the 20s through the period.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Very stagnant aviation conditions will continue through the next
24 hours. Ceilings will remain generally MVFR, lowering some
during the overnight hours, and then lifting some tomorrow
afternoon. A brief period of IFR ceilings is possible at KDAY
early tomorrow morning. Winds are expected to remain out of the
NNE through the TAF period, generally at or below 10 knots.
Some snow will impact areas south of Cincinnati tonight, and
flurries are possible at KCVG/KLUK, but with no expected impacts
to warrant inclusion in the TAFs.
OUTLOOK...MVFR ceilings will continue through Friday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Clark
NEAR TERM...Hatzos
SHORT TERM...Clark
LONG TERM...AR
AVIATION...Hatzos
Area Forecast Discussion
National Weather Service Paducah KY
643 PM CST Thu Jan 7 2021
.UPDATE...
Issued at 643 PM CST Thu Jan 7 2021
Updated aviation discussion.
&&
.SHORT TERM...(Tonight through Saturday night)
Issued at 310 PM CST Thu Jan 7 2021
As often is the case, some tricky mesoscale banding of
precipitation occurred with the strong closed upper-level low over
the southwest Tennessee area. A very narrow but persistent band
has been oriented from west to east from about Van Buren MO to
Vienna IL to nw Kentucky today. The western end of the band has
pivoted in place, allowing some localized snow totals in the 1 to
3 inch range over Carter County.
The main concern through the evening is the evolution of this
mesoscale band. The band has partially fallen apart on radar as of
2030z. However, hrrr and namnest guidance depicts a banding
feature well into the evening along or just north of the 20z
location of the band. This would roughly line up from kevv to just
south of kmdh. Since the band has averaged only 10 to 15 miles
wide, the exact location is barely within the ability of the high-
res models to resolve. Therefore, pops will only be in the chance
category tonight. The hwo and sps will highlight the potential
for minor impacts in the general area where banding is forecast.
Thus far, main roads outside of Carter County have stayed
generally wet under the heaviest precip.
By 12z Friday, the main story will be cold northerly winds on the
back side of the departing system. A solid low overcast is
forecast to persist most of the day Friday. The moist and
unstable boundary layer will be conducive for some flurries or
isolated measurable snow showers. Highs will be in the 30s.
A 500 mb shortwave will rotate southeast across the mid
Mississippi Valley Friday night and early Saturday. This system
will keep abundant cloudiness in place. A few snow showers cannot
be ruled out, but the forecast remains dry for now. Even with the
clouds and some wind, lows will fall into the 20s Friday night.
Some partial clearing is likely Saturday, but the pattern will not
be conducive for much clear sky. A broad area of mid-level
troughing will continue to encompass much of the eastern and
central states. Negative 500 mb height anomalies will be focused
over the lower Mississippi Valley. Highs will again be in the 30s,
with lows in the 20s.
.LONG TERM...(Sunday through Thursday)
Issued at 310 PM CST Thu Jan 7 2021
At the beginning of the extended forecast period, the medium range
numerical model suite has slight ridging in place aloft, while a
broad 1030-1034 mb surface high remains across the WFO PAH forecast
area. Models do take the current low off the Pacific northwest
Coast and dive into Oklahoma and northern Texas on Sunday. This low
and the attendant precipitation advected northward from the Gulf of
Mexico is expected to remain along and just south of the WFO PAH
forecast area in the lower Mississippi Valley during the afternoon
and evening on Monday. The models vary a little bit by Tuesday
morning, with some guidance opening the low into a progressive upper
wave moving northeast into central Tennessee and central Kentucky by
daybreak Tuesday.
At this point in time, trended PoPs very slightly upward over the
southeast Purchase and southern Pennyrile regions of west Kentucky.
Suspect there will be a little wiggle room during the next several
model runs for PoPs, but the current forecast is relatively well
blended with adjacent NWS offices. Given the QPF amounts at this
time, it looks like a sub-advisory mixed precipitation event late
Monday afternoon and evening, but you never know given any banded
mesoscale potential on the western/northern quadrant of the low.
Given the trend toward opening up as a wave, lift may be
marginalized with time.
Look for some rise of max/min temperatures near or above normals for
this time of year, as ridging develops behind the low.
&&
.AVIATION...
Issued at 643 PM CST Thu Jan 7 2021
Though cigs will be quite variable at times, MVFR conditions will
generally become more and more dominant across the region tonight
while an upper low rotates through central and eastern TN.
Meanwhile, light pcpn, mainly in the form of snow or rain, will most
likely occur over southwestern IN and adjacent parts of western KY
through midnight. Much of the pcpn will remain aloft unless a
concentrated band sets up. North-northeasterly winds AOB 12 knots,
with slightly higher gusts at times, will back to a northerly
direction by daybreak Fri.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...MY
LONG TERM...Smith
AVIATION...DB