Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/22/17
Area Forecast Discussion
National Weather Service Albany NY
947 PM EST Tue Feb 21 2017
.SYNOPSIS...
A weak disturbance approaching from the eastern Great Lakes will
move across the area tonight, bringing chances for light rain or
light freezing rain in some spots. Mild conditions with well above
normal temperatures are then expected to build in for the remainder
of the week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 930 PM EST...Not much change to ongoing forecast as line
of showers continues to advance east, however, our 00Z sounding
is drier than compared to previous forecasts. This has resulted
in upstream showers diminishing a bit as they advance eastward.
Mesonet observations do show near freezing temperatures in the
Mohawk Valley, Adirondacks, northern Berks into the southern
Greens. So no changes to the advisory at this time.
Prev Disc...Freezing Rain Advisory in effect for portions of
the Southern Adirondacks, Lake George Saratoga Region, Central
Mohawk Valley, western Schenectady county, northern Taconics,
southern Vermont and the Berkshires from 8 pm this evening to 6
am Wednesday.
Temperatures have warmed into the mid 30s to mid 40s across the
region this afternoon, although a very dry air mass remains in place
with surface dewpoints in the teens to lower 20s. So when light
precip arrives this evening/overnight, wet bulb cooling is expected
and temperatures should drop into the lower to mid 30s.
An upper level disturbance and jet streak quickly moving across the
region this evening and overnight will result in some light
precipitation developing. Output from hi-res guidance such as the
HRRR and the 4km NCEP WRF continues to indicate greater coverage of
precip than the lower resolution models such as the NAM/GFS. So will
continue to mention 40-60 pops for much of the area with scattered to
likely coverage.
Temperatures expected to cool to around or slightly below freezing
for portions of the area, mainly north of and outside of the Capital
District. Even though QPF will be light, we have issued a Freezing
Rain Advisory for a Trace to 0.05 inches of ice. Even trace amounts
can cause a driving/walking hazard on untreated surfaces, thus
opting for the advisory.
Light rain will occur for areas outside the advisory, with precip
generally ending before sunrise Wednesday as the disturbance quickly
moves eastward. A few sprinkles will be possible early Wednesday
morning.
Lows tonight will generally be in the upper 20s to mid 30s with
temperatures rising a few degrees towards sunrise Wednesday.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
The main story for the short term period of the forecast will be
very mild temperatures. Milder air will start to build in on
Wednesday, with temps aloft warming to around +5C to +6C. Mixing
does not look very favorable to reach full warming potential though.
Some breaks of sunshine are expected to develop by late morning and
afternoon, so will mention high temps in the mid 40s to lower 50s.
Relatively cooler locations will be north of the Capital District,
but still quite mild for late February.
Mild temps continue Wednesday night, with the entire area expected
to remain above freezing with lows mainly in the mid to upper 30s
due to a light southerly flow. A few showers may brush portions of
the western/southern Adirondacks with a disturbance approaching from
the Great Lakes. Patchy fog should develop across areas with
snow still on the ground.
Zonal flow aloft to persist on Thursday, with even warmer conditions
expected. Forecast soundings indicating better mixing potential,
although degree of cloud cover is somewhat uncertain. At this time
will mention partly sunny skies for most of the area. Highs could
approach or exceed 60 degrees in some valley locations depending on
how much sunshine can occur. The record high for Albany Thursday is
62 degrees set back in 1984. Cooler lower/mid 50s expected over the
Adirondacks and southern Greens with more cloud cover.
A short wave ridge of high pressure will briefly build in Thursday
evening, but a warm front approaching form the Midwest and Ohio
Valley will bring increasing chances for showers late Thursday night
into early Friday morning. Mild temps continue, so plain rain
expected for p-type.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As mentioned in previous discussions, an active period of weather
is expected through this last weekend of February.
Highly energetic jet interacting with increasing baroclinic zone
over the center of the nation will aid in the development and
strengthening surface low across the mid and upper Mississippi River
Valley and through the Great Lakes region. Downstream impacts will
be a warm front lifting north with clouds and the chance for light
precipitation to develop through Friday into Friday evening. As low
level jet increases to 50kts or greater, this will assist with
advecting warm and moist air over a snowpack. This should result in
patchy fog and the chance for drizzle with little diurnal
temperature drop expected.
The main impact day still remains on Saturday. GEFS PWAT anomalies
remain 2-3 standard deviations above normal with v-component of the
925-850mb winds approaching 5 standard deviations above normal. This
is ahead of a digging trough that evolves toward a negative tilted
pattern. Given a highly dynamic pattern, expectations are for
periods of moderate to period of heavy rain, snow melt (where recent
NOHRSC suggests 10-12" of water equivalent was present in the
mountains) and the chance for thunderstorms as Showalter Values drop
to around 0C from the global model consensus.
Frontal passage occurs during the early evening Saturday as H850
temps drop from near +10C on 18z/Sat to -10C 18z/Sun. This will set
the stage for lake effect snow to develop downwind of Lake Ontario
for portions of the Dacks and western Mohawk Valley. Furthermore,
strong gusty winds are expected due to tight pressure gradient and
around 40kts at H850.
Another fast moving clipper type system is expected to race across
the region for early next week. However, moisture profiles appear
disconnected as chances for precipitation appear slight chance at
this time.
Temperatures will be on a unique swing from well above normal to
near or below normal through the weekend.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
VFR expected into the evening hours tonight as mid and high
clouds increase and gradually lower throughout the evening. A
weak system has the potential to bring some light/MVFR rain
showers after 03Z tonight, with a chance for some FZRA in the
high terrain, mainly at KPSF. There is also potential for IFR
conditions to develop prior to dawn with moisture becoming
trapped beneath a lowering inversion north of KPOU. Have
continued the previous forecast of prevailing IFR at KGFL/KPSF
after 09Z for the time being with gradual improvement back to
MVFR towards the end of TAF period.
Southerly winds are 5 to 10 kts with some gusts up to 20 kts
for KALB. Winds will then slacken overnight tonight through
Wednesday.
Outlook...
Wednesday Night: Low Operational Impact. Patchy FG.
Thursday: Low Operational Impact. Slight Chance of SHRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday: Moderate Operational Impact. Chance of SHRA...DZ.
Friday Night: Moderate Operational Impact. Slight Chance of SHRA...DZ...FG.
Saturday: High Operational Impact. Definite SHRA...TSRA.
Saturday Night: Moderate Operational Impact. Chance of SHRA...SHSN.
Sunday: No Operational Impact. NO SIG WX.
&&
.HYDROLOGY...
No widespread hydro problems are expected through the rest of the
work week, with just light precipitation forecast and overnight
temperatures falling into the upper 20s and 30s the next few nights.
However, mild temperatures that will be well above normal, are
expected for later this week. This will cause snowmelt and
subsequent runoff. Also, a strong storm system may bring a period of
moderate to heavy rainfall on Saturday. The Meteorological Model
Ensemble River Forecasts /MMEFS/ continue to suggest significant
river rises will occur, with flooding possible Saturday into Sunday
due to the combination of snow melt and locally heavy rain.
At this time, at least minor flooding appears likely for a few to
several points along main stem river. Depending on the degree of
snow melt, flooding could reach moderate levels in some locations.
We will have more specific information as the weekend draws
nearer.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Freezing Rain Advisory until 6 AM EST Wednesday for NYZ033-
039>043-048-054-082>084.
MA...Freezing Rain Advisory until 6 AM EST Wednesday for MAZ001-025.
VT...Freezing Rain Advisory until 6 AM EST Wednesday for VTZ013>015.
&&
$$
SYNOPSIS...11/JPV
NEAR TERM...BGM/JPV
SHORT TERM...JPV
LONG TERM...BGM
AVIATION...Thompson/JVM
HYDROLOGY...11/JPV
Area Forecast Discussion
National Weather Service Columbia SC
942 PM EST Tue Feb 21 2017
.SYNOPSIS...
Above normal temperatures will continue through the week.
Moisture associated with an onshore flow will support a
chance of showers through Friday. A cold front will cross the
region Saturday with dry high pressure building into the area
for the start of next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
An onshore flow will occur in the forecast area associated
with high pressure moving off the Mid-Atlantic Coast and low
pressure in the northeast Gulf of Mexico. Latest CAE radar
continues to indicate a few sprinkles/light showers over
portions of the Midlands and CSRA late this evening. The
precipitation is very light resulting in mainly trace amounts. The
lingering effects of upper ridging will help keep moisture
shallow and should limit showers. The latest HRRR model
displays little coverage and will continue to forecast low
pops overnight. The low- level moisture combined with nocturnal
cooling will likely lead to low clouds and fog late tonight.
The overnight low temperatures look reasonable.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Closed low pressure over the eastern Gulf of Mexico on
Wednesday will gradually shift southeastward and cross the
southern tip of the Florida Peninsula on Thursday. Surface high
pressure over the Mid- Atlantic coast will ridge into the
forecast area from the northeast on Wednesday and will shift
further east into the Atlantic on Thursday. This may promote
weak in situ wedge development on Wednesday in the northern
portion of the area. The wedge may linger just north of the area
on Thursday. Moisture will deepen across the area with surface
winds out of the east/southeast. Precipitable water values will
peak at around 1.3 inches Wednesday afternoon/evening.
Isentropic lift combined with increased moisture transport will
promote a chance of showers on Wednesday. Models show lower
precipitable water values on Thursday with drier air aloft
moving into the region so have continued to indicate only a
slight chance of showers. Kept high temperatures a little lower
on Wednesday with the possibility of a wedge, although still
around 10 degrees above normal. Went with highs on Wednesday in
the lower to middle 70s and middle to upper 70s on Thursday.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
The models take the closed low through the Bahamas on Friday
where it weakens and lifts toward the northeast. A low pressure
system located over the Midwest will track northeastward on
Friday and bring a cold front into the forecast area Saturday.
Models show the front moving through the area relatively quickly
with much drier air returning to the area in the wake of the
front by Saturday evening. Continued to indicate only a slight
chance of pops associated with the front. Surface high pressure
and drier air will settle into the forecast area late Saturday
through Sunday. Modified Pacific air mass with cooler temps but
still projected to be above normal. Nearly zonal upper flow
across the southern states expected to continue late in the
forecast period as well, with systems moving rapidly. A quick
moving trough will track east across the country, with it and
the surface low staying to our north. Surface high to shift east
ahead of it Sun night into Monday, with moisture return for our
area Mon/Mon night into early Tue. Any chance for precipitation
will be low.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Low-level onshore flow will continue across the area overnight.
Models indicating shallow low-level moisture through the night.
The low-level moisture combined with nocturnal cooling will
likely lead to the development of low clouds and fog late
tonight. The guidance was consistent indicating IFR conditions
developing tonight.
The hrrr model shows isolated showers through 06z, and this is
currently being shown on regional radar loops. Will include
mention of vcsh in tafs, although much of the activity will be
light, consisting of mainly sprinkles or a brief light shower.
Remainder of the period after 06z appears mostly dry for now.
EXTENDED AVIATION OUTLOOK....
Moisture associated with an onshore flow may help bring periods
of widespread MVFR or IFR conditions through Friday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion
National Weather Service State College PA
1009 PM EST Tue Feb 21 2017
.SYNOPSIS...
An extended period of mild weather with well above normal
temperatures will continue through the end of this week. A weak
cool front will push through the state late today and tonight.
A stronger cold front is expected for Friday into Saturday,
followed by a shot of colder air with gusty westerly winds over
the upcoming weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Late evening regional radar mosiac continues to show fractured
frontal shower band sagging southward across north central and
central PA and progressing eastward from western PA this
evening...with isolated sprinkles entering the Laurel Highlands
along the MD border.
With the northern and southern streams disengaging from one
another, higher rain chances overnight are split to the north
and south of central PA. Latest HRRR still starts to fill
shower activity in during the pre dawn hours across the central
mountains, but overall very light QPF expected with the front
overnight into Wednesday morning with most areas seeing a trace
to a few hundreths of an inch at most.
We have yet another very mild night in store with temperatures
averaging 15-25 deg above normal.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
The weak cold front will either stall or fall apart right over
the local area later tonight and Wed. Model soundings suggest a
fair amount of cloudiness hanging in over the state, but we will
probably not see more than a stray shower in a few spots.
Sunshine, mixed with varying amounts of clouds will be the
rule. Considering the mild start to the day, and GEFS mean 850
mb temps of 7-8C, we should see max temps easily reaching the
upper 50s to lower 60s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Gradually milder temperatures will return for the extended
period as no genuine cold air push is in sight. High
temperatures in general will be 10 to 20 degrees above normal
with min temperatures mainly above freezing.
Deepening Swrly flow for the second half of the week will cause
temps to rebound to well above normal (and perhaps near record
levels in some locations).
The overall, large-scale pattern becomes more amplified late in
the week as a system over the central plains deepens and lifts
into the Great Lakes. Clouds will increase Thursday and Friday
with warm front lifting through, and bringing increasing rain
chances heading into the weekend, followed by a shot of
colder/windy conditions Saturday through Sunday.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A weak and weakening cool front will push through the state
tonight. A stronger cold front is expected for Friday into
Saturday.
Widespread VFR will continue tonight for most of central PA
even as mid-clouds thicken and lower ahead of a weakening front
approaching from the Midwest. The exception will be across the
NW 1/3 of the airspace where MVFR ceilings will become likely
along with a period of light rain showers late this evening
into early Wednesday morning.
Sub VFR conditions will be most likely the first half of Wed
over the higher elevations from the Laurels to the northern
mountains, with conditions improving back to VFR during the
afternoon.
Outlook...
Thu-Fri...Mainly VFR with possible rain showers and brief
restrictions.
Sat...LLWS. Strong FROPA with sub-VFR likely in moderate rain
showers. Isolated TS psbl. Post-frontal NW wind gusts 25-35kts
psbl with snow showers NW 1/3 Saturday night into early Sunday.
Sun...Sub-VFR Laurels up into the Northern Mountains along with
scattered lake enhanced snow showers. Brisk NW winds.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...DeVoir/La Corte
SHORT TERM...La Corte
LONG TERM...Lambert/Gartner
AVIATION...RXR
Area Forecast Discussion
National Weather Service Nashville TN
830 PM CST Tue Feb 21 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Light precipitation continues to drift northward across Middle
Tennessee this evening, and the latest version of the HRRR shows
scattered showers lasting the duration of the night. Hourly
temperature observations have been running a little cooler than
forecast grids, so have nudged overnight lows downward in order to
compensate. No other changes are being made at this time.
&&
.AVIATION...
00Z TAF DISCUSSION.
While things aren`t too bad right now, flight categories will
begin to degrade over the next few hours. Cigs and vis will fall
to MVFR/IFR overnight with light rain across the mid-state. These
conditions are very likely to persist into morning hours before
starting to improve from west to east around 17Z Wednesday. MVFR
could persist into the afternoon hours, however.
Winds will be a little breezy early this evening before settling
down as we approach 06Z. Those early breezes will be mainly
southerly and back to the east as they relax.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......08
AVIATION........Unger
Area Forecast Discussion
National Weather Service Paducah KY
527 PM CST Tue Feb 21 2017
.UPDATE...
Updated aviation section for 00z taf issuance
&&
.SHORT TERM...(Tonight through Thursday night)
Issued at 247 PM CST Tue Feb 21 2017
Look for isolated and banded segments of light precipitation to
continue to drift northeast to east through the evening hours,
generally east of the Mississippi River. The NAM-WRF (ARW/NMM
versions), as well as the RAP guidance, seem to have a fair
handle on the precipitation field.
Cloud cover will be some what problematic overnight, as parts of
Southern Illinois, Southeast Missouri, and the Purchase area of
West Kentucky will be under a col, limiting efficient scouring of
moisture across the area. There will be some variable clearing
across the aforementioned area as the lower clouds and cirrus
erode slowly from the northwest into the WFO PAH forecast area.
Given the variability in cloud cover and radiational loss
(inducing thermal gradients), there will be some potential for
locally dense fog between 2 am and 9 am CST. For now, plan to
issue a general special weather statement alluding to the
potential overnight, but will leave any final go/no go decision
for a dense fog advisory to the evening forecast crew.
With low to middle level shortwave ridging in place, could see a
slower evolution of clearing and/or development of partly to
mostly cloudy skies across the WFO PAH forecast area during the
day on Wednesday due to weak mixing under the capping layer aloft.
Even with this cloud cover, the WFO PAH forecast area could still
see high temperature records tied or broken.
Stronger warm air advection will take place on Thursday, with some
slight erosion of the cap (south of the warm front) over
Southeast Missouri and Southern Illinois late Thursday night. With
the exception of Friday (in the extended forecast period), there
could be near record setting high temperatures again on Thursday.
At this point, current forecast temperatures may still be underdone
by 1-3 degrees. Still holding out that some location in the WFO
PAH forecast area will flirt with temperatures near 80 by the end
of the workweek.
.LONG TERM...(Friday through Tuesday)
Issued at 247 PM CST Tue Feb 21 2017
Models remain in good agreement, and they have been for quite a
while, showing a cold front moving across the PAH forecast area on
Friday. Models indicate pretty good instability along and ahead
of the front, and SPC has outlooked eastern portions of our
region. So thunderstorms seem a good bet on Friday, especially in
the afternoon hours. We may see some sunshine in the morning
hours, and with some gusty south winds, high temperatures will
reach the upper 60s to middle 70s.
The front will push east of our region by 06z Saturday, and showers
and storms will quickly end by late Friday evening. Colder air will
filter in behind the front, with low temperatures dropping into the
middle 30s to lower 40s. High pressure will briefly take hold
across our region for the weekend, with the center of the high
moving over our area Saturday night. With mostly clear skies and
northwest winds, temperatures will actually be near to even a few
degrees below seasonal normals Saturday through Sunday.
By late Sunday into Sunday night, the ECMWF shows a warm front
lifting across the middle Mississippi valley. The GFS and Canadian
are a bit slower with this feature, and just went with slight to low
chances for light showers across much of our area Sunday evening. We
should be dry late Sunday night, then both ECMWF and GFS show
widespread precipitation developing and spreading east by Monday
evening due to an approaching low pressure system and cold front.
Instability increases by Monday night, so went with slight to low
chances for showers on Monday, with increasing chances for showers
and slight chances for thunderstorms Monday night into Tuesday.
Southerly flow will lead to a significant warming trend for the
beginning of the work week, with readings again well above seasonal
normals Monday and especially Tuesday.
&&
.AVIATION...
Issued at 527 PM CST Tue Feb 21 2017
Main concern for tonight is the potential for fog and low stratus.
Cigs early this evening will remain primarily vfr, though areas of
mvfr are likely in light rain across western KY and extreme se
Missouri. Later on tonight, the thick overcast is forecast to become
thinner or possibly scatter out. If this occurs, conditions would be
highly conducive for dense fog with light winds and rain-moistened
ground. The most likely area for this to occur is north and west of
kpah, and dense fog will be forecast at kcgi. Fog and stratus will
likely increase at all sites right before sunrise, when radiational
cooling will be strongest. It will take some time for the low clouds
and fog to burn off Wed morning, and even in the afternoon cigs will
only improve to mvfr.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...Smith
LONG TERM...RST
AVIATION...MY