Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/20/20
Area Forecast Discussion
National Weather Service State College PA
947 PM EST Sun Jan 19 2020
An upper level trough will swing through the northeast CONUS
early in the upcoming week. High pressure will then settle over
the region for the second half of the week bringing perhaps
the coldest air of the season.
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
LE still enducing clouds and -SHSN as of 02Z. There are some
large breaks in the cloud deck over Warren and McKean Cos,
though. After chatting with BUF and CLE, we agreed that we can
probably drop the LES flags as additional accums will be very
minor, maybe no more than a dusting. Clearing may come
begrudgingly but the HRRR soundings for BFD show the inversion
crashing into the ground around sunrise. Kept sky cover a little
more pessimistic than total clearing, though. The llvl flow will
still be out of the NW all night and into the daylight. Expect
mins in the teens and upper single digits. The north may be the
spot to bust (too cold of a forecast) if the clouds do not go
away appreciably. But, they only have to dip 5-6F to get to the
curr fcst mins. Holding the line.
.SHORT TERM /7 AM MONDAY MORNING THROUGH WEDNESDAY/...
Aside from some early day snow showers over the northwest
mountains and Laurels, Monday will be cold and dry and feature
max temps similar to today`s (Sunday), that will range from the
upper teens to lower 30s in the SE. These temps are about 6-7F
below climate normals for Mid January.
Upper ridge and elongated surface high build over the eastern
U.S. early in the upcoming week, keeping the rest of the
workweek mainly dry with chilly temps 5-10 degrees below normal
through midweek. Tuesday and Wednesday mornings will feature
some of the coldest air of the season so far.
Temperatures should moderate to near normal by Wed afternoon, as
the main axis of the high pressure system moves east of our
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
After a couple of cold days, temps should rise back to normal on
Wed and keep climbing a few degrees each day. Even after The
potential precip next weekend, temps do not look like they would
go back below normal. CPC 6-10 day temperature out look is well
above normal, and the 8-14 day is near to above normal for
An upper level shortwave trough will move into the Pac NW on
Tuesday and dig southeastward into the Great Plains region by
Friday morning. Some model discrepancies between the ECMWF,
with a more amplified solution, and the GFS with more zonal
flow. In the 12z Sun ECMWF run, the upper low closes off by
Saturday morning and passes south of our area, keeping us in the
colder air as some wintry precip spills into the southern half
of PA Saturday night. In the 12z Sun GFS run, the upper trough
passes over Erie, PA with a broad frontal system moving across
the area, with a wintry mix at onset going over to rain as
warmer air moves in Saturday, and then back to snow showers
behind the cold front Sat night. Ensemble guidance tending
towards the GFS so far. Not a surprise given the pattern we have
been in, with generally zonal flow and storm tracks going west
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
MVFR teetering on IFR conditions for BFD owing to scattered
lake effect snow showers through the first part of tonight.
MVFR conditions at JST for cigs w occasional drops in vis as
isolated snow showers move through. VFR expected this afternoon
elsewhere. Gusty westerly winds will continue through early
Mon-Tue...Mainly dry, but still a chance of snow showers across
Winter Weather Advisory until midnight EST tonight for PAZ004.
Area Forecast Discussion
National Weather Service Wilmington NC
1103 PM EST Sun Jan 19 2020
Arctic air will build into the Carolinas early this week. High
pressure will remain to our north through Wednesday, then should
move offshore Thursday. An area of low pressure should bring
showers late Friday into Saturday, along with milder temps.
The secondary cold front currently pushing across the FA,
should move south of the FA by midnight. In it`s wake,
cold and dry air will infiltrate the region, complements of a
1045+ mb Arctic high pressure with it`s center now located
across the North Central United States. Have tweaked temps and
winds to account for current conditions and trended them toward
the overall fcst by midday Mon.
Have tweaked the winds(including gusts) and seas slightly
upward to account for current conditions and latest hourly progs
ie. HRRR and NWPS. SCA conditions to last likely to midday Mon
with plenty of low level mixing over the local waters, a result
of the Arctic air moving across mild ocean SSTs, relatively
.NEAR TERM /THROUGH MONDAY NIGHT/...
Initial cold front is now offshore, along with all the light rain.
Secondary cold front across our western areas, where dewpoints are
dropping quickly, skies are clearing, and winds are become west-
northwesterly. Surface high pressure builds in across the central US
behind the front, setting up a very cold and dry start to the week.
Temps drop to around 30 degrees tonight, and only rise to around 40
degrees Monday under strong cold advection. Add in slightly breezy
north winds tomorrow afternoon and dewpoints in the teens, and it
will truly feel like winter after a week of spring. Current forecast
low for Monday night is around 25 degrees, though model guidance has
been trending downward with these values.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A powerful positively tiled upper trough will pivot across the
Southeast states Tuesday, exiting the Georgia and South Carolina
coast Tuesday night. 500 mb temperatures below -30C are well
below the 10th percentile values for winter and may rank among
daily record low values at CHS. Despite the strength of the
system aloft, low-level baroclinicity will be focused from the
Bahamas to Bermuda, too far south and east to develop a surface
system that could lead to precipitation for us. Mainly clear
skies and cold conditions are forecast as the low-level cold
pool drops into the Carolinas Tuesday, then moves offshore
After highs only in the lower 40s Tuesday, forecast lows are in
the mid-upper 20s Tuesday night. This is above most MOS
guidance as it appears there will be sufficient wind, especially
near the coast, to keep the boundary layer well-mixed all
night. Temperatures should moderate Wednesday and Wednesday
night as warm advection begins and skies remain mostly sunny.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
The only system of interest in the extended forecast is expected
to move across the Carolinas Friday night, bringing a 12-hour
window of rain. Timing with this system has improved
considerably among the various models over the past 12-24 hours,
and I`ve increased PoPs to 60 percent (likely) for Friday night.
High temperatures look like they`ll rebound back into the 60s
(above normal) for Friday and Saturday.
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
Gusty NW winds have relaxed now that the sun has set and mixing has
weakened considerably. Wind dir remains N to NW overnight into
tomorrow as high pressure builds in and the sky remains clear.
Extended Outlook...VFR conditions thru next week. Arctic high
pressure will dominate.
Small Craft Advisory for nearshore waters has been extended through
7am tomorrow morning as seas remain elevated and winds increase
again tonight behind secondary cold front. Wilmington Harbor buoy
off of Cape Fear currently recording 8ft 6sec S waves. Expect
southerly swell heights to slowly decrease through the night into
morning. Current westerly winds veer to NW this evening and
northerlies by morning, sustained around 20kts overnight with gusts
around 25kts. Winds remain northerly Monday and Monday night around
15 kts, with seas 2-4 ft, a 5-6 sec NE wind wave, as the southerly
swell dies down by early tomorrow.
Arctic high pressure across the Ohio Valley will push cold air
out across the waters on Tuesday on northerly winds. Developing
low pressure well off the Georgia coast will help to accelerate
wind speeds to a solid 25 knots with higher gusts late Tuesday
into Wednesday. The potential for even stronger winds out over
the Gulf Stream probably means we`ll be dealing with a combination
of north wind chop and an east or northeast swell. Small Craft
Advisory conditions appear likely.
By Thursday low pressure offshore should accelerate out past
Bermuda and high pressure will settle across the Mid-Atlantic
region. Wind speeds should finally diminish. A warm front ahead
of the next low pressure system organizing to our west on
Friday should lift a warm front north across the coastal waters,
with winds becoming southeast to south by Friday night.
MARINE...Small Craft Advisory until noon EST Monday for AMZ250-252-254-
Area Forecast Discussion
National Weather Service Lincoln IL
853 PM CST Sun Jan 19 2020
Issued at 330 PM CST Sun Jan 19 2020
Very cold conditions will persist across central Illinois
tonight with temperatures remaining steady in the single digits
and teens. A few flurries will be possible as well...particularly
during the evening.
Issued at 853 PM CST Sun Jan 19 2020
As an upper level trough axis continues to slip southeastward, an
area of clearing has developed over north portions of central IL
this evening, continuing to slip southeastward. At the same time,
plenty of light flurries have been noted in the observations
around central IL. The 00Z ILX sounding shows a couple of thin
cloud layers situated within an ideal dendritic growth zone of
temperatures, due to the cold air mass over the area, which is the
reason for the prevalence of flurries. Otherwise, winds are still
a breezy 10-15 mph mph from the northwest, and temperatures are in
the upper single digits in the northwest to upper teens in the
southeast. This is well on track with forecasts, and should result
in temperatures dropping to the low single digits northwest to low
teens southeast, as well as wind chill temperatures ranging from
near zero to minus 10. Updates this evening have been mainly for
cloud cover trends as well as flurries.
.SHORT TERM...(This evening through Monday)
ISSUED AT 330 PM CST Sun Jan 19 2020
A short-wave trough extending from New York to north-central
Illinois has resulted in a band of low clouds/flurries across the
KILX CWA this afternoon. Partial clearing has occurred in the wake
of the wave across southern Wisconsin into northern Illinois:
however, this clearing has been making very little progress
southward over the past couple of hours. HRRR has been
consistently showing the clouds clearing from north to south late
this afternoon into early this evening, but based on satellite
trends think this is too aggressive. Think partial clearing will
occur along/north of a Peoria to Bloomington line this evening,
with mostly cloudy conditions holding firm further south across
the remainder of the area. May even see a few snow flurries
through the evening...as evidenced by several 21z/3pm obs along
the I-74 corridor. Thanks to the cloud cover and continued
northwesterly winds, temperatures will remain nearly steady in the
single digits and teens.
Next weather-maker is already evident on latest water vapor
imagery over southwest Manitoba. This wave is progged to dive
southward over the next 24 hours, with the strongest lift skirting
central Illinois to the W/SW Monday afternoon. Despite both the
12z and 18z HRRR keeping measurable precip well to the west
across northern/central Missouri, other models such as the 12z
WRF-ARW and 18z NAM bring very light amounts to the far southwest
CWA. With the wave tracking so close and the very cold airmass
remaining in place, would not be surprised to see light snow
along/southwest of a Macomb...to Springfield...to Effingham line.
Any accumulations will be limited to a dusting, with a few tenths
of an inch further west along/west of the Mississippi River. High
temperatures will range from the teens in the Illinois River
Valley to the middle 20s near the Indiana border.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 330 PM CST Sun Jan 19 2020
Temperatures will steadily warm through the middle of the week,
with highs climbing back into the upper 30s to around 40 degrees
by Wednesday. After that, a stronger system will come into the
picture for the middle and end of the week. Models have
consistently been showing a slow-moving southern stream feature
spreading clouds and light precip into west-central Illinois
perhaps as early as Wednesday night...with the main flux of precip
holding off until Thursday night into Friday. While light snow
accumulations will be possible both Wed night and Thursday night,
temperatures will be too warm to support snow during the day...as
highs approach 40 on Thursday, then rise into the lower to middle
40s on Friday. End result, will be an extended period of off-and-
on light precip Wednesday night through Friday night...mostly in
the form of rain.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 543 PM CST Sun Jan 19 2020
MVFR cigs are in place across the central IL terminals although
partial clearing is working its way southward from northern IL.
This clearing is expected to reach KPIA and KBMI within an hour or
two, however sites to the south are more debatable and may take
several hours to see partial clearing. Additional cloudiness is
likely to arrive overnight: from lake-effect from Lake Michigan
at KCMI, and from a weather system dropping southward out of
Manitoba. Scattered snow flurries with little or no visibility
impact can be expected early this evening, and additional
flurries or snow showers may impact KSPI vicinity after 17Z
Monday from the approaching weather system. Winds NW 9-14 kts
initially, slowly decreasing to 5-10 kts overnight.
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
758 PM EST Sun Jan 19 2020
Issued at 758 PM EST SUN JAN 19 2020
Low stratocu is advecting in from the northwest this evening. RUC
guidance has had a decent handle on these clouds, and it suggests
mostly cloudy skies filling back in across eastern Kentucky
through the night. Some flurries have also been noted at times in
upstream observations. As such, did expand the flurries across the
area. For temperatures, made some minor adjustments for this early
evening update. Given that mid to upper teens are on the doorstep
of the Bluegrass, wound up lowering the values a bit there.
Further downstream, have bumped up some of the valley lows, as
most of the ridges should be colder once again tonight, given the
continued cold air advection through 850 mb, as well as the
prevalent low clouds. Updates have been sent.
.SHORT TERM...(This evening through Monday night)
Issued at 352 PM EST SUN JAN 19 2020
The period will be dominated by a large eastern CONUS upper
trough, and large, arctic, surface high pressure`s center slowly
moving from the northern plains this evening to the mid
Mississippi Valley by Tuesday morning. This will keep cold air in
place for our area. Steep low level lapse rates beneath a frontal
inversion, coupled with just enough moisture, will result in
varying amounts of clouds. They will be most prevalent over the
eastern part of the area, aided by flow which came off the Great
Lakes. The moisture in the mixed layer will reach into the
dendritic growth zone at times, resulting in some flurries-- once
again most prevalent over the eastern part of the area.
A shortwave trough currently dropping out of manitoba will move
south southeast in the larger scale upper level trough during the
period, crossing our area Monday night. It`s main influence will
be to our west, but even there any precip will be vary limited due
to a lack of moisture.
.LONG TERM...(Tuesday through Sunday)
Issued at 302 PM EST SUN JAN 19 2020
The extended portion of the forecast begins on Tuesday with an
amplified upper level pattern in place. This pattern continues to
be highlighted by a stout ridge over the central Plains as this
begins to shift east. This pattern allows northwest flow into the
Great Lakes and the OH Valley to begin the period. The long wave
trough will remain over the east for the first part of the
extended but will begin to shift east as the ridge moves east into
the OH Valley by Wednesday. Despite the amplitude in the pattern,
features will move with some decent progression as the ridge will
move east of the Appalachian Range and along the East Coast by
Thursday night. This sets the stage for a transition to an active
pattern as a deepening trough over the Plains crosses the MS
Valley and into the lower OH Valley. The ridge however, gains some
strength and builds along the East Coast. This will work to slow
down the approaching trough and keeping active weather over the
area for the rest of the extended. For the most part, the models
have a good handle of the upper level trends with a pretty
consistent run to run solution. There may be some differences in
the Day 6 and Day 7 period but some confidence can be put into the
Concerning the lower level features, colder air still hanging around
from the intrusion of the Arctic Airmass in northwest flow and
still just enough lower level moisture will keep the chance of a
few lingering flurries on Tuesday morning. After this, surface
high pressure sets into place keeping mainly clear skies for the
rest of the day on Tuesday and Tuesday night. The calm winds and
clear skies Tuesday will allow for some 5 to 10 degree ridge to
valley differences on low temperatures as some lower teens are
possible in the valleys. After the morning lows, as the surface
high eventually shifts east throughout the day on Wednesday
allowing southerly winds and warmer temps advecting into the
region and moderating the Arctic Airmass. The next chance for
precip will then arrive Thursday night with the approach of the
next system. The high to the east slowly giving way to the arrival
may delay precip into eastern Kentucky possibly until Friday with
downslope winds possible. Overnight lows into Friday morning may
support a tenth of accumulation of snowfall but with downslope
being a possibility, no accumulation is expected. A lack of
instability seems to be the case as well so precip through much of
the event seems to be stratiform. As of now, the ridge keeping
the system in place over the area from Friday morning through
Saturday night seems to be a long duration but QPF in total is
lacking. WPC totals agree with the NBM at this time with no more
than an inch over a 48 hour period in expected. No hazards are
expected at this time in the extended.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 758 PM EST SUN JAN 19 2020
MVFR ceilings will build back in across eastern Kentucky through
this evening from northwest to southeast. The low clouds will
persist through the overnight, before gradually diminishing or
raising from southwest to northeast during the day on Monday, with
VFR conditions returning in the afternoon. Northwest winds of 5 to
10 kts, will veer to the north through the period.
Area Forecast Discussion
National Weather Service Nashville TN
938 PM CST Sun Jan 19 2020
FOR EVENING DISCUSSION.
While most of the Mid State has been cloud-free today, there is a
blanket of low clouds sinking south across the TN/KY state line
tonight. Latest RAP soundings and model guidance suggest this
cloud cover will continue to spread south overnight. Adjustments
to the near-term forecast were made and temperature trends will
continue to be monitored.
In addition, a few flurries have been reported in Kentucky as
cloud cover inches south. Very cold temperatures are accompanying
this layer of clouds, so the production of a snowflake or two
cannot be ruled out. However, confidence in flurries remains too
low to include in this update.
Cold temperatures are the top story for overnight, with values
already in the upper teens and low 20s at 9 PM. For pets
normally outdoors, consider bringing them inside for warmth
00Z TAF DISCUSSION.
VFR. Just a few stratocumulus clouds are expected this TAF period
with brisk northwest winds gradually becoming more northerly