Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/20/19
AREA FORECAST DISCUSSION
National Weather Service Binghamton NY
814 PM EDT Fri Apr 19 2019
A large slow moving low pressure system will move from the
Tennessee Valley through the Mid-Atlantic region into the
weekend, bringing periods of heavy rain and a few thunderstorms
to most of the area tonight. On and off rain showers with mild
temperatures this weekend into next week.
.NEAR TERM /THROUGH SATURDAY NIGHT/...
8 pm update...
Minor update to tonight`s forecast. Forecast in good shape. A
surface boundary has moved south into the Finger Lakes. Behind
it is stable air with temperatures around 50. On the south side
of it temperatures and dewpoints around 60. The Chemung basins
are getting the best rain now but that will move east.
345 PM Update...Latest GOES-East water vapor and IR satellite
loop continue to show a deep moisture fetch extending from the
Florida peninsula, across the Carolinas, Mid-Atlantic and now
entering PA. The upper level circulation continues to spin over
Alabama/Mississippi increasing the moist, southerly flow into
our area. Surface temperatures have risen into the upper 60s to
mid-70s areawide, with dew points rising into the upper 50s and
near 60 already. SPC mesoanalysis shows PWATs rising fast
(1.3-1.5 inches) as the area of moderate to heavy rain and
embedded thunderstorms rides north across east-central PA. Low
level moisture transport is impressive, with a strong low level
jet, upwards of 50 kts expected at 850mb later this evening. The
warm cloud layer will be approaching 9000-10000 ft through this
event. There is also some surface based and ML CAPE present
across NE PA and the NY southern tier; mainly less than 350 J/Kg
into the late evening. Overall the set up remains favorable for
periods of moderate to locally heavy rainfall with embedded
thunderstorms across much of the area this evening and into
tonight. The heaviest batch of rain likely impacts the area from
about 9PM to 3 AM.
SPC continues to advertise a marginal risk for an
isolated strong to severe storm over the Wyoming Valley region
of NE PA this evening...with the main threat being isolated
strong, gusty thunderstorm winds. There is around 40 kts of bulk
effective shear in place.
Latest radar and mesoscale model trends show the heaviest rain
axis shifting a bit west from earlier runs. There still remains
uncertainty on exactly where this narrow band of the heaviest
rain ultimately sets up; current forecast put this across
Bradford, Wyoming, Chemung, Tioga, Broome and Chenango counties.
In this area a solid 1-2 inches of rain is forecast, with
localized amounts around 3 inches also possible. Expanded the
flash flood watch a bit west, to now included Steuben, Schuyler
and Tompkins counties. The entire watch area still looks to
receive between 1-2", with locally higher totals. Used a blend
of the latest guidance, including WPC, RFC and some of the HRRR
for our official QPF amounts. Further north, outside of the
watch area expect a soaking 0.75 to 1.50 inch rainfall. Main
stem rivers are still expected to remain mostly below flood
stage; but smaller creeks and perhaps a few flashier headwater
points could get into minor flooding.
The rain looks to gradually taper off from west to east after
2-5am tonight, exiting the eastern areas toward or just after
daybreak Saturday. Much of the area gets into a dry slot from
later Saturday morning into the afternoon. There will be some
marginal instability, so could still see a scattered pop up
shower. Think there will be some breaks of sun during the day
and very mild temperatures as southerly winds increase between
10-20 mph once again. Highs will reach 65-75 areawide.
Saturday night: The upper level low continues to slowly spin
over the Appalachians and will bring more cloud covers and
perhaps an isolated shower to the region. Our area finally gets
under the cold pool aloft, so low temperatures will be cooler;
in the 40s to near 50.
.SHORT TERM /SUNDAY THROUGH MONDAY/...
3 pm update...
An upper level low over WV will move northeast through PA sunday
and Sunday night. Moisture and forcing with this will cause
some showers especially in the afternoon and evening due to
diurnal heating. Sunday ahead of the low, high temperatures get
into the 60s. The airmass is only slightly colder with the upper
level low. Monday highs again in the 60s with more showers.
Lows Sunday night in the 40s.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
3 pm update...
Models have come into better agreement but that won`t take much.
both Euro and GFS have a low lifting northeast along a frontal
boundary with another round of showers Tuesday afternoon into
Tuesday night. That track of the low will make a difference on
the high temperatures. With the current track to the north and
approaching late in the day, temperatures should get into the
upper 60s and lower 70s. Lows again mostly 40s.
Wednesday drier and cooler air moves in behind the low. Still a
few showers and temperatures peak mid 50s to mid 60s far south.
On Thursday some signs of the frontal boundary sinking to our
south leaving a dry day. Again Thursday morning lows mainly in
the 40s with highs in the 60s.
Friday an upper level trough could send a cold front southeast
into the area with showers. Temperatures similar again with
lows 40s, highs 60s.
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
730 pm update...
Complicated forecast as lower conditions close in from the
north, west, and south. Generally cigs and vsbys fall this
evening to IFR/low MVFR then slowly improve Saturday. Adding to
that is the chance of thunderstorms at least AVP and maybe into
NY. Also some low level wind shear at AVP.
Surface boundary dropping south into SYR/ITH with IFR cigs and
MVFR vsbys around 05z. RME also falls to IFR around this time.
ELM/BGM also fall to IFR cigs around 06z as steadier rain moves
in. AVP should only fall to fuel alternate MVFR.
CNY sites return to MVFR around 16z. AVP/ELM go to VFR around
18z but other sites hold onto MVFR a few more hours.
At AVP south winds 10 kts but at 2k feet 40 kts. In NY winds
shifting to east or even northwest behind the front. Winds
speeds of 5 to 10 kts. On Saturday Winds shift to the south and
increase to 10 to 15 kts with higher gusts.
Saturday Night...Mainly VFR.
Sunday through Monday...Restrictions possible in rain showers.
Tuesday Night and Wednesday...Restrictions possible in periods
PA...Flash Flood Watch through Saturday morning for PAZ038>040-043-
NY...Flash Flood Watch through Saturday morning for NYZ022>025-
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
1048 PM EDT Fri Apr 19 2019
For tonight periods of rain...locally heavy at times...will continue
into Saturday. This rainfall combined with higher elevation
snowmelt will cause significant rises on many streams and rivers
with multiple rivers reaching flood stage by Saturday.
Additional showers are likely on Saturday, especially across
Vermont with a large range in temperatures anticipated due to a
sharp cold front in the area. Cooler and unsettled weather
continues for Sunday into early next week.
.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 1048 PM EDT Friday...Flood Watch continues with no big
changes at this time. We continue to see waves of precipitation
moving up across the area with the Saint Lawrence Valley seeing
a half to just over an inch of rain with a steady decrease in
precipitation amounts as one heads east. That will be changing
as more waves of precipitation over the mid-Atlantic states
move north-northeast up into the region. Will not take much to
get higher rainfall amounts everywhere and more noticeably rises
on area waterways will be taking place as the night wears on.
Only tweak was to match the sharp thermal gradient across the
Flood Watch goes into effect this evening at 6 PM and continues
until Noon on Sunday.
Still anticipating multiple rivers to reach flood stage and several
to approach moderate flood stage by Saturday based on the
Northeast River Forecast Center`s latest forecasts.
Isolated convection this evening into the overnight hours could
produce higher rainfall rates with localized flash flooding
possible, especially across the higher trrn of the Dacks into
the mountains of VT.
Forecast challenge continues to be placement of heaviest
precipitation axis through Saturday, but general trends have been
for a slight shift south with axis from northern NY into
central VT, for widespread 1 to 2 inches expected and isolated
higher amounts possible.
Water vapor shows an impressive closed 5h/7h circulation across the
MS Valley with deep moisture advection across the entire eastern
CONUS. In addition, classic baroclinic leaf is present, indicating
region of strong upper level divergence from rrq of 150 knot jet and
multiple rounds of convection is observed upstream. Surface
analysis shows sharp boundary slowly sagging south across the
SLV and northern/central CPV as of early this aftn, with temps
well into the 70s and dew points in the 50s ahead of this
front. This strong low level convergence will serve as the focus
for multiple periods of showers with enhanced higher rainfall
rates in the warm sector associated with stronger convective
elements through the overnight hours. The best 925mb to 850mb
fgen forcing and associated rainfall will extend from northern
NY into northern VT, while the best instability with capes of
300 to 800 J/kg and deeper convection will be from eastern Dacks
into central/southern VT. Other ingredients supporting
widespread moderate to localized heavy rainfall is pws climbing
btwn 1.0 and 1.5 inches, strong IVT signal, good south to
southwest nose of 850mb jet of 40 to 50 knots, and favorable jet
position, helping to enhance deep synoptic scale lift. Given
pockets of elevated instability lingering throughout the
overnight hours, a few embedded rumbles of thunder cannot be
rules out, especially southern cwa. High resolution NAM 3km,
HRRR, BTV4km, and RAP13 all indicate this potential.
For Saturday...Deep closed 5h/7h circulation slowly moves east with
strong mid level southerly flow prevails. The forecast challenge for
Saturday is the placement of well defined dry slot and axis of deep
tropical moisture feed from the Atlantic. GFS continues well defined
mid level dry slot impacting most of our cwa on Saturday, while
RAP/NAM and HRRR show deep layer moisture with additional threat for
showers with heavier rainfall amounts. Thinking this scenario looks
reasonable, given deep cutoff of system with negative tilt, which
will help to advect deeper moisture into VT. Will mention likely to
cat pops with additional rainfall expected. eventually dry slot
develops btwn 18-21z and steadier rainfall should exit to our east
with just scattered showers overnight Saturday. Guidance shows warm
front lifting back north with 925mb temps climb btwn 15-16c on
Saturday, resulting in very mild temps and more high elevation snow
melt. Expecting highs mid 60s to mid 70s, with mid slopes well into
the 50s, especially eastern sections. If clearing can develop in dry
slot, temps could be warmer.
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 252 PM EDT Friday...A generally cloudy and warm day is
expected on Sunday while cut off low lifts north. Relatively dry
air in place will prevent widespread showers, but vort maxes
spiraling along the upper low as well as orographic lift will
keep slight chance for showers across higher terrain. Towards
Sunday night, upper low sluggishly advances northeast and deep
moisture will begin to return. A surface low will develop off
the Mid-Atlantic Coast and increase chances for precipitation
Sunday night mainly across portions of southern and eastern
Vermont. Highs forecast to be in the mid 60s to lower 70s and
lows in the 40s.
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 252 PM EDT Friday...Weather pattern remains unsettled. Low
pressure continues to slowly lift towards the Maine Coast, bringing
showers mainly to eastern VT. This shifts eastward Tuesday and
precipitation gradually decreases until a shortwave dives east
from the Great Lakes late Tuesday. This is followed by yet
another, stronger shortwave on Wednesday. This initiates
development of a coastal low with wrap around precipitation
keeping chances for showers, mainly in the Northeast Kingdom,
going through Wednesday. The best weather day looks to be next
Thursday, when a brief upper ridge builds into place. Quiet
weather will be short-lived with another system reaching the
North Country next Friday. Temperatures above normal, then
become near normal on Wednesday, and then trend back upwards.
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Through 00Z Sunday...Ceilings and visibilities will continue to
lower through 04z as widespread precipitation moves into the
region. Expect IFR to LIFR conditions to develop during this
time period and then persist through about 12z. Areal coverage
of the precipitation will decrease over the area as bulk of the
steadier precipitation gradually shifts east of the region.
There will be improvement to the visibilities...climbing into
MVFR and VFR categories...but ceilings will generally remain in
the IFR category. Winds will generally be under 10 knots through
the period with turbulence expected aloft.
Saturday Night: VFR. Chance SHRA.
Sunday: VFR. Slight chance SHRA.
Sunday Night: Mainly VFR, with local MVFR possible. Slight chance
Monday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Monday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Tuesday: Mainly VFR, with local MVFR possible. Chance SHRA.
Tuesday Night: Mainly VFR, with local IFR possible. Likely SHRA.
Wednesday: Mainly MVFR, with areas IFR possible. Chance SHRA.
As of 332 PM EDT Thursday...A Flood Watch goes in effect at 6 PM
and continues until Noon on Sunday for the entire North Country.
We continue to expect a moderate to locally heavy rainfall
event heading into the weekend, especially northern NY into
most of VT, with sharp rises anticipated on many rivers and
streams. Several main stem rivers are expected to reach minor
flood stage with the potential for moderate flood stage for some
of the northern rivers with higher snow melt.
In addition, embedded higher rainfall rates could produce an
isolated flash flood threat during this time period, especially
across complex terrain of the Adirondacks into mountains of VT.
Specific river rises will be dependent on exactly where the
heavy rainfall occurs so please follow the latest rainfall and
river forecasts for flooding. Main stem rivers most at risk
for flooding include the Passumpsic, the Wells, the Missisquoi,
the Lamoille, the Winooski, the Ausable, and the Saranac Rivers.
Sharp river rises will begin tonight, with most rivers expected
to crest on Saturday.
Additionally, Lake Champlain continues to slowly rise with current
levels over 99 feet. With the additional rainfall and snow melt
this weekend, the Lake Champlain level will likely approach or
exceed 100 feet this weekend or early next week.
Those with interests in low-lying or flood prone areas should
continue to monitor the latest forecasts.
VT...Flood Watch through Sunday morning for VTZ001>012-016>019.
NY...Flood Watch through Sunday morning for NYZ026>031-034-035-087.
Area Forecast Discussion
National Weather Service State College PA
1044 PM EDT Fri Apr 19 2019
A slow moving cold front will move through the region later
this evening and overnight. Unsettled weather will hang around
through the weekend as the associated upper air disturbance
crawls eastward. Much of the time from later Sunday into mid
week will be dry, but no long term dry spells are seen at this
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Last counties removed from SVR Watch #92. As SVR/TOR threat
winds down, still some hydro concerns as line of locally
training convection in rich PW environment lifts up the Lower
and Middle Susq River Valleys through the early morning hours.
PW in excess of 1.5" surging north on the nose of a southerly
35-60kt LLJ ahead of negative tilted upper trough and strong
upper diffluence/large scale uvvel. Selective areas of higher
CAPE support scattered thunderstorms capable of heavy rainfall
rates in excess of 2 inches per hour. The window of heaviest
rain will be closing by around midnight with the HRRR taking the
deepest convection east of the CWA. Scattered showers will
continue into Saturday however.
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Dry slot should bring a decrease in shower activity east of the
Alleghenies to start the weekend. Despite some clouds, high
temps should manage to peak around 70 degrees from the central
mountains into the Susquehanna Valley. Cooler temps and most
likely area of showers should be across western PA. Saturday
looks like the better day for the upcoming holiday weekend.
Falling heights and gradually cooling temps aloft associated
with slow moving upper level low will spread shower risk to the
east across most of central PA on Easter Sunday into Sunday
night. Temperatures will trend cooler but max climo departures
are only about 5 degrees from mid April averages.
.LONG TERM /MONDAY THROUGH FRIDAY/...
Expect improving conditions/dry wx early next week as high
pressure moves into the area behind departing upper level low.
Look for a nice rebound in temperatures with highs in the 65 to
75 degree range on Tuesday. 80F not out of the question in the
Lower Susquehanna Valley Tuesday afternoon.
There is decent model agreement in the next frontal system
moving into or through the area around midweek. Beyond
Wednesday, guidance shows a large divergence in the evolution of
the boundary and overall precipitation pattern. Trends seem to
lean toward wet vs. dry into the second half of next week but
confidence is low. Temperatures are likely to cool off from
Tuesday`s highs before trending warmer into next weekend.
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Showers and embedded thunderstorms will continue to overspread
the flying area into the evening hours. Localized downpours are
expected, and a few of the thunderstorms could produce strong winds.
Expect widespread flight restrictions into tonight.
Unsettled, showery weather will persist into Saturday and
possibly Sunday as well.
Sat...Widespread restrictions in the morning with some
improvement despite continued chc of showers.
Sun...Scattered showers and areas of sub-VFR.
Mon-Wed...Mainly VFR with scattered showers.
Flash flood watch expanded westward earlier today coincident
with shift/trend in the hires models and HREF mean QPF.
River (small stream) flooding threat remains largely predicated
on exactly where (location) the heavy rain falls. That said,
still expecting widespread 1-2 inches across most of central PA.
Hydro models still show minor flooding on the Swatara Creek at
Harper Tavern and Middletown. The lower mainstem Susq. small
streams/tribs remain very vulnerable to quick rises and most
susceptible/likely to experience short duration flooding.
Smaller, quick responding streams in the Juniata and WB Susq.
should also be monitored for potential flooding.
Several-foot rises are fcst on larger rivers with fcst crests
above caution/action levels at Harrisburg and Williamsport later
Saturday into Sunday.
Flash Flood Watch through Saturday morning for PAZ012-018-019-
NEAR TERM...DeVoir/La Corte
Area Forecast Discussion...CORRECTED
National Weather Service Gray ME
1039 PM EDT Fri Apr 19 2019
Expect showers to form this evening along a frontal boundary.
Rain will be heaviest over the mountains of New Hampshire and
western Maine. Coastal areas will still see some rain, but not
as much as further north. Expect there to be some areas of fog
as well. A cold front moving through on Sunday will bring drier
conditions. Unsettled weather will remain in place across
northern New England into next week.
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1030 PM Update...A few minor adjustments to temperatures and
PoPs for the next few hours based on latest obs and radar
imagery. 70 Degrees at the Portland Jetport as of the 10 PM
observation...impressive and a long time coming! Even hearing
"peepers" outside of the office here a for the first time this
The stationary front continues to waver around near the Canadian
border with some far northern towns in the forecast area in the
40s. Otherwise, south of the boundary we continue warm overnight
with even some slightly muggy conditions in places. No major
changes to the forecast at this time.
630 PM Update...Have updated the forecast mainly for minor
adjustments to temperatures and PoPs based on latest
observational data and latest mesoscale model output. Timed the
PoPs close to the HRRR for the next 6-12 hours or so. Have added
a slight chance of thunder to all zones for later this evening
and overnight. Nose of 70 kt LLJ will impinge on the forecast
area later this evening bringing plenty of forcing for ascent to
support high PoPs for rain. In addition, added moisture and
slightly steeper mid level lapse rates will support a couple of
embedded thunderstorms. Warm front continues quasi-stationary
across central Somerset County ME...with readings in the 30s and
40s there. South of the front will be remain quite warm with
lows in the 50s and 60s.
Southerly flow this afternoon has allowed temperatures to climb
well above normal. This will likely have at least some impact on
overnight low temperatures. Expect them to be a bit higher than
The bigger story though, will be the rain. As low pressure
begins to move north out of Virginia, showers will form along
the stalled frontal boundary draped across the region.
Initially, the showers will be confined to New Hampshire and the
western mountains of Maine. As the low pressure center moves
north of the Mason-Dixon line though, the precipitation will
become more widespread. We should see showers across the entire
region, but the QPF amounts will be highest over the
aforementioned areas of NH and the Maine mountains. The warm and
moist flow will likely generate some areas of fog tonight as
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
The low pressure system moves every so slowly into western PA
and western NY states tomorrow, while the frontal boundary
remains stalled over our area. The primary area of QPF tomorrow
will shift further east, over the coastal plain. The warm
temperatures of today, coupled with continued warmth overnight
tonight and tomorrow, will generate some flooding issues. Please
see the hydro section for more on that. Continued warm and moist
conditions will keep fog in the forecast for the overnight
.LONG TERM /SUNDAY THROUGH FRIDAY/...
The bulk of the precipitation will shift to far eastern
portions of the forecast area on Sunday. A band of showers will
likely continue, extending poleward from well of the Mid
Atlantic coast to the Mid and Downeast coast of Maine. We will
continue to remain in the warm sector with temperatures topping
out in the 60s during the day.
Rainfree conditions are expected Sunday night into early Monday
morning as the precipitation continues to shift east and into
the Canadian Maritimes. However, 12Z model runs are in
relatively good agreement swinging the upper level support into
northern New England during the day Monday through Tuesday
An active weather pattern will continue as more upper level
support dives southeastward and into the forecast area on
Wednesday. This will trigger cyclogenesis during the middle part
of the work week. This system will also be followed by cooler
air entering the region from Canada. There will potentially be a
changeover to snow in the northern mountains with this feature
as noted by the latest Canadian and European model runs.
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term /Through Saturday Night/...VFR conditions this
afternoon will quickly deteriorate tonight to IFR/LIFR
conditions as fog sets up and rain moves in. Expect the IFR
conditions to continue through tomorrow and tomorrow night.
Long Term...Most sites gradually improve to VFR conditions on
Sunday with areas of IFR conditions along the coast during the
morning. MVFR conditions Monday in lowered ceilings and
precipitation which will continue at times Tuesday and
Short Term /through Saturday Night/...Southerly flow will keep
SCA conditions in the forecast through at least tomorrow. Seas
will be slow to come down, and the SCA that is currently in
effect will likely need to be extended into tomorrow night.
Persistent S-SE flow will keep seas in the 7-11 feet range
through Sunday, mainly in the open waters. SCA winds will
likely persist through Saturday night.
The question is where will the axis heavy rain will be located.
A front will sink south into Maine and bisect the area from
east to west Saturday. The exact location of this front will
have a big impact on precipitation amounts and temperatures.
Currently we are looking at a 1 to 2 inch rainfall. This will
certainly be enough to bring many rivers to minor flood stage
when combined with snowmelt. Moderate flooding is possible.
High astronomical tides this weekend will combine with a
prolonged onshore southerly flow to potentially lead to minor
beach erosion and splashover. Minor coastal flooding is
possible. Any impact would occur tonight and Saturday night.
ME...Flood Watch from 8 AM EDT Saturday through Sunday afternoon
NH...Flood Watch from 8 AM EDT Saturday through Sunday afternoon
MARINE...Small Craft Advisory until 8 AM EDT Saturday for ANZ150>154.
Area Forecast Discussion
National Weather Service Northern Indiana
920 PM EDT Fri Apr 19 2019
Issued at 322 PM EDT Fri Apr 19 2019
Some showers will move across the area into this evening before
one last round of widespread rainfall arrives tonight and persists
into Saturday. Additional rainfall amounts through Saturday
afternoon will range from less than one quarter of an inch across
far northwest Indiana and extreme southwest Lower Michigan to
around an inch along and east of the Interstate 69 corridor.
Otherwise, cool and windy conditions are expected today with high
temperatures only reaching the mid and upper 40s. Below normal
temperatures will continue into Saturday before high temperatures
warm back into the 60s and lower 70s for Sunday under mostly sunny
Issued at 920 PM EDT Fri Apr 19 2019
Latest satellite, radar, and surface obs show an aggressive push
of dry air in our NW zones with little/no precip in all but our
far eastern zones. Latest model guidance (notably the hi-res/rapid
refresh models) also trending slower and further SE with upper
low and associated deformation band track. Have therefore made
some substantial cuts to PoPs/QPF in our northwest zones and
adjusted the timing a bit for all areas. Further adjustments may
be necessary as some guidance (mainly RAP and HRRR) suggest precip
will not push much further north than US-24. There will also be
an incredibly sharp cutoff between moderate rain in the
deformation zone and no precip/sunny skies just to the northwest.
Did not go too aggressive with new PoP and Sky grids given some
lingering uncertainty in exact location of deformation but could
easily see further trimming necessary if trends in hi-res guidance
.SHORT TERM...(This Evening through Saturday)
Issued at 322 PM EDT Fri Apr 19 2019
Extensive cloud cover has kept temps in the mid 40s across the
area with a stiff NE wind now taking shape as stout upper level
low pressure dropping into Mississippi will eventually come back
northeast tonight into Saturday to bring one more round of rain to
the area. Deformation zone will quickly setup and pivot NW to
impact at least the SE half of the area, but will take till after
closer to the 9Z Sat window given how far south the upper low
currently is with precip lingering into 15 to 18Z. Models still
varying on exactly how far NW it comes with a tight cutoff
expected closer to Lake Michigan where not a drop of rain may
fall. Rainfall amounts of one half to 1 inch look on track SE half
and quickly tapering from there. Lows will drop into the upper
30s, but precip should stay all rain (although can`t entirely rule
out a bit of snow mixing in). Rain will move out Saturday
afternoon with skies clearing somewhat in far W/NW areas where
highs may climb into the 50s vs another raw day in the 40s where
the clouds and rain linger.
Flooding concerns have diminished given that the expected QPF
overnight didn`t fully pan out with mainly rises into action stage
on several rivers and continuation of standing water in fields.
HWO will be toned down somewhat.
.LONG TERM...(Saturday Night through Friday)
Issued at 322 PM EDT Fri Apr 19 2019
Models generally in agreement on closed upper low near the KY/WV
border at the start of the period, slowly filling as it works East
to the East coast by 12Z Mon. This will allow the end of rain for a
few days as 574 dm ridge axis shifts over the region at the same
time. Clearing skies Sunday will allow for warmer low level temps to
be mixed down, with highs in the 60s. Clouds will increase Monday in
advance of a the first of 2 systems, the first a weak northern
stream disturbance moving out of the Plains. Models agree to some
extent with minor differences in timing and strength, but all
warranting chc pops for some showers/isol storms. Next system
remains more problematic with models refusing to agree on handling
of southern stream trough and potential phasing with a northern
stream wave. Agree with previous forecaster that best course for the
time being will be to maintain a dry forecast with seasonable temps
in the 60s.
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 800 PM EDT Fri Apr 19 2019
For KFWA...fuel alternate ceilings likely to persist for bulk of
the period as upper low slowly lifts NE. Latest guidance trends
have been a little slower and further SE with deformation band
slated to push into our area late tonight/Sat. Therefore have
lower confidence in IFR/heavier rain impacting KFWA but will leave
a TEMPO mention. Otherwise...expect showers to persist through
much of Sat with ceilings holding in low MVFR category.
Drier air currently working into KSBN and expect VFR stratus to
slowly scatter through this evening. There is a low chance for
some brief MVFR stratus to return late tonight as moisture/
deformation band try to push NW but will hold with VFR for now
given latest guidance trends noted above. Skies will be entirely
clear during the day Saturday.
LM...Small Craft Advisory until 11 PM EDT Saturday for LMZ043-046.
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AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1059 PM EDT Fri Apr 19 2019
Issued at 1059 PM EDT FRI APR 19 2019
Band of showers and storms continues to pivot northward across
northeast and far eastern Kentucky. This activity will shift off
to the north over the next hour or two, leaving behind generally
dry weather for much of the remainder of the night. Updated grids
to reflect latest trends.
UPDATE Issued at 920 PM EDT FRI APR 19 2019
Band of heavier showers has been pivoting northeast across east
Kentucky over the past few hours as the center of the low
pressure system is shifting overhead. A pronounced dry slot is
moving northward behind this band of precipitation and will likely
bring a lull for eastern Kentucky through the second half of the
night after this current band of precipitation pivots northward
and out of the area by midnight. Wrap around moisture will begin
to move back into our southwestern zones by dawn. Updated the pops
and weather to reflect these trends.
.SHORT TERM...(This evening through Saturday night)
Issued at 421 PM EDT FRI APR 19 2019
The afternoon surface analysis shows frontal boundary slowly
moving into eastern Kentucky this afternoon. This boundary has
pushed east on a line from Lewis County back to Clinton County
based on Kentucky Mesonet observations. The surface low is now
centered in the heart of Eastern Tennessee this afternoon, and
this feature will be a player for eastern Kentucky late this
afternoon and evening. This feature will slowly pull north and
east, as a upper level low digs and slowly progresses north and
east through the period. We have been able see some clearing
across our far south and this is leading to MUCAPE values in the
250 to 500 J/kg range this afternoon. Even though we are seeing
the better clearing the winds are backing to the southeast and
this is leading to a downward trend in dewpoints/moisture. This
will yield drier conditions and this would also cut into the
overall severe threat. The guidance and even the recent SPC
mesoanalysis data suggests we will have ample effective shear of
30 to 40 knots and increasing to 50 to 60 knots over the next 4 to
6 hours. This could prove to be too much shear for the amount of
CAPE generated in this environment. However, the surface low
leading to more rapid pressure fails and upper level forcing for
ascent could make up some for the deficiency in the instability.
This leads to an isolated and more conditional risk for strong to
even severe storms late this afternoon and evening. Overall the
main risks would be gusty winds, but hail could be a factor given
the lower freezing levels. However, the low topped nature and high
shear could leave you with less resonance time for hail growth.
The CAMs do show some storm cells developing this evening, with
the HRRR showing activity underneath the deepening surface low by
19/23Z to 20/04Z timeframe. There are also isolated updraft
helicity swaths showing up suggesting more organized storms could
develop. This will be closely monitored through the evening where
additional updates can be made.
This low will track right across eastern Kentucky, with a
TROWAL/deformation zone setting up further west into central
Kentucky. A previously mentioned boundary will lead to lowering
temperatures and this will lead to more cold rain showers through
the night into Saturday. The lower freezing levels based on the
model soundings suggest some locations in the highest terrain
could see temperatures lowering around freezing by Saturday
morning. This will lead to mixing or changing to snow in some
cases mainly along the higher terrain near the Virginia and
Tennessee borders. The clouds and cold air advection should lead
to a cold day for even spring standards across the eastern
Kentucky Saturday. There will also be lingering showers, as the
upper level low and surface low track nearby the area. The rain
showers will linger into Sunday night mainly in the far east, and
clouds will also be slower to clear given the upper level low just
to our east. This will lead to fairly uniform temperatures Sunday
night under weak winds and cloud skies. The low temperatures will
bottom out into the upper 30s to lower 40s.
.LONG TERM...(Sunday through Friday)
Issued at 510 PM EDT FRI APR 19 2019
The last of any remaining precip from Saturday`s system will be
exiting to the east on Sunday morning as the associated upper low
weakens and moves further northeast of our area. Surface high
pressure is then expected to remain nearby from Sunday afternoon
into early Tuesday, as ridging aloft passes over. This will result
in mainly clear skies. Light winds and good radiating conditions
will allow for chilly temperatures by Monday morning. Some patchy
frost can`t be ruled out in our coldest valleys, but will hold off
on its mention at this point. Outside of this, the building
geopotential heights and abundant sunshine will bring a warming
trend through Tuesday.
After this, a negatively tilted upper trough will move east and
work to flatten the aforementioned ridge. A weak cold front will
accompany the upper trough. Moisture will advect over the area in
advance of the front and lead to our next prospect of rain coming
in from the northwest late Tuesday. Models have not honed in on
common solution to handle this system going into the later portion
of the week. The ECMWF wants to close off an upper low at the tail
of the aforementioned upper trough and tracks it slowly across
the southeast CONUS late in the week. Meanwhile, the GFS maintains
an open wave which moves more quickly eastward. The GFS ensemble
mean shows support for the GFS operational run, and ECMWF trended
faster with the upper low. In light of this, it supports leaning
toward the GFS, with lower POPs on Friday.
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 920 PM EDT FRI APR 19 2019
IFR ceilings will be seen west of a line from KSYM to KLOZ
overnight with MVFR ceilings or higher to the west as an area of
low pressure moves nearly directly overhead of east Kentucky
overnight. As wrap around moisture moves back over the area on
Saturday, a mix of MVFR and IFR conditions can be expected through
Area Forecast Discussion
National Weather Service Pendleton OR
525 PM PDT Fri Apr 19 2019
VFR conditions are expected thru the TAF period. However there are
some TSRA over the area that could locally impact the TAF sites
for the next few hours mainly ALW, BDN, RDM. Reduced cigs psbl if
TSRA impacts an individual arpt. SHRA will continue overnight and
decrease durg the mrng and cdfnt moves thru from w to e.
.PREV DISCUSSION... /issued 200 PM PDT Fri Apr 19 2019/
SHORT TERM...Tonight through Sunday night...WSR-88D is showing
increasing returns with showers developing over the southern Blue
Mountains northeast to Wallowa County. Few cloud-to-ground strikes
detected in southern Wheeler County near Mitchell. Showers and
scattered thunderstorms are developing ahead of a cold front
currently moving across central WA and northwest OR. The HRRR has
been consistent with most thunderstorm activity in Union and Wallowa
Counties this evening. MLCAPES around 600-900 J/kg and 35-40 knots
of bulk shear could mean strong thunderstorms capable of penny size
hail and heavy rain.
The front will gradually make its way across the forecast area this
afternoon and evening. The upper level jet is parallel to the
front, resulting in a slow-moving system. Keeping this in mind, QPF
was increased over north central and northeast OR and far southeast
WA tonight. 0.25-0.5 inch of rain is possible over the Blues and
Wallowas overnight and up to 0.25 inch of rain elsewhere. Previous
models indicated the upper level trough moving into Idaho Saturday
with drier air from the north-northwest, but the timing is slower.
Therefore, numerous showers will continue Saturday morning
throughout central and northeast Oregon then tapering off to
scattered showers in the afternoon and evening. After midnight on
Sunday morning, the only showers left will be over the Wallowa
Mountains. It will be a perfect day for outdoor activities and
Easter egg hunting on Sunday with mostly sunny skies and highs in
the mid-50s to mid-60s...near 70 in the Lower Columbia Basin and
surrounding valleys. Wister
LONG TERM...Monday through Saturday. Monday and Tuesday, there
will be a ridge of high pressure with temperatures about 10 degrees
above normal and mainly dry conditions. The ridge is expected to
flatten slightly on Wednesday with some moisture pushing into the
Blue Mountains and models indicate some instability, so have kept a
slight chance of thunder for this area as well. A trough of low
pressure will be nearing the coast on Thursday with some moisture
and instability ahead of it. Currently, models keep this a little
further south of the forecast area so I have not mentioned thunder
at this time. A large trough of low pressure remains over the area
on Friday into Saturday with a mainly dry west to northwest flow.
This will also usher in some cooler air with temperatures cooler to
near normal levels. 93
AVIATION...18Z TAFs...Showers will spread across the area this
afternoon and tonight. There will also be a chance of thunderstorms
this afternoon and evening over central Oregon and the eastern
Oregon mountains. Have opted to leave mention out of forecast for
BDN/RDM as coverage of storms may be just to east of this area. Cigs
will be 035-080 with MVFR cigs possible in heaviest showers. Showers
will continue overnight decreasing from the northwest by early
morning. West to northwest winds will increase to 10 to 20 kts with
higher gusts this afternoon from 20Z-03Z. 93
HYDROLOGY...Flood Warnings continue for the Grande Ronde river at
Troy and John Day river at Service Creek as warm temperatures and
some heavy rain will increase runoff over the next few days. 93
.PRELIMINARY POINT TEMPS/POPS...
PDT 48 60 40 65 / 60 60 10 0
ALW 50 61 43 67 / 50 50 10 0
PSC 52 68 44 72 / 40 30 0 0
YKM 47 67 41 70 / 20 10 0 0
HRI 51 66 43 70 / 40 40 0 0
ELN 42 62 38 66 / 10 10 0 0
RDM 45 57 35 63 / 70 70 10 0
LGD 47 53 39 60 / 80 60 30 0
GCD 46 51 38 61 / 80 70 30 0
DLS 50 65 43 67 / 40 20 0 0