Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/07/18
Area Forecast Discussion
National Weather Service Albany NY
1006 PM EDT Mon Aug 6 2018
.SYNOPSIS...
An isolated shower or storm is possible to the north and
west of Albany, otherwise tonight will be warm and humid with no
rain for most places. Tuesday will be another hot and humid day.
A weak cold front may bring some thunderstorms to the region on
both Tuesday and Wednesday, some of which may contain gusty winds
and heavy rainfall. Dry weather will return on Thursday, but
temperatures will remain a little above normal through the rest
of the week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
As of 1006 PM EDT, showers and thunderstorms have dissipated in
the NWS Albany forecast Area. A few cells just southwest of the
area near Binghamton,NY and another cell just northeast of
Washington County in Vermont. Only clouds are across the
northwest part of the forecast area. Temperatures are generally
in the 70s with 60s over the southern Adirondacks and Albany and
Schenectady hanging in the low 80s. Latest run of the HRRR
shows mainly dry conditions for the remainder of the night, with
some showers reaching the far northwest part of the forecast
area around daybreak with the approaching weak cold front.
Previous...
A few isolated storms are developing south and east
of Lakes Erie and Ontario late this afternoon. Based on the 12z
BUF sounding there is a cap around 500 mb and deep layer wind
speeds are only around 15 kts up through 500 mb. Based on this
environment expect storms to struggle to grow much past 15000 to
20000 feet east of Lake Ontario through early this evening and
storm type should be pulse. These storms could reach as far east
as the southern Adirondacks or maybe the central Mohawk Valley
through about 6 or 7 pm before weakening with the sunset. The
overnight will be dry across the area with clouds increasing
from the west toward morning ahead of the next front.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
A cold front will approach the area on Tuesday. Mid-to-upper
level forcing is not very strong with this next system and mid-
level height falls will be minimal, however there does appear to
be a low-level frontal boundary that will cross the area from
west to east late in the day. This will combine with a very
warm, moist airmass to trigger some thunderstorms Tuesday
afternoon into the evening. With lack of mid-level height falls,
mid-level lapse rates will be modest, around 5-6 degrees C per
km, and MLCAPE values will likely be near to just over 1000
J/kg during the afternoon. Deep layer shear will be marginal for
organized convective with 0-3 and 0-6 bulk shear values
expected around 25 kts. The CAMs are generally indicating a
broken line of convection to move across the area Tuesday
afternoon, however the convection does not appear to be very
intense. Based on all of this we expect some thunderstorms
Tuesday afternoon with a few storms probably approaching severe
limits, but not a significant severe potential. Overall the SPC
outlook for marginal severe appears to be reasonable. With the
warm, moist atmosphere any storm will also contain very heavy
downpours as precipitable water values approach 2.0 inches.
Meanwhile we will keep a heat advisory going for Tuesday
afternoon for lower elevations. Clouds should keep temperatures
down a few degrees lower than today but we are still looking for
highs in the upper 80s with dew points into the lower 70s which
will result in heat indices near threshold advisories for
advisories into the mid 90s.
Another system will approach the area on Wednesday. This system
appears to have more upper-level support but with clouds and a
somewhat cooler atmosphere MLCAPE values with this system should
be marginal for stronger convection with values generally below
1000 J/kg. Deep layer wind speeds also do not appear to be
overly impressive with values only around 20 kts. The
atmosphere will still be quite moist and locally heavy rains
appear to be the greatest threat with these storms at this
point.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
This period will be typical of mid-summer, with daytime high
temperatures mainly around 70 degrees in the high peaks to the
lower 80s in the valley regions, though Friday will be an even
warmer day from the Capital Region on south. The overnight lows
will be mostly from the upper 50s to mid 60s.
With little atmospheric momentum, and no big high or low pressure
areas, humidities will be elevated, but not oppressive. A
nearby quasi-stationary front will bring the greatest risk for
showers and storms during the weekend and into the start of the
work week, with a trend toward lessening storminess, and the
greater risk for showers across the southern portion of our
forecast area.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR conditions expected at the TAF sites through midnight.
Conditions will again be favorable for the development of fog
overnight. Expect MVFR/IFR at all TAF sites late tonight.
Conditions become VFR by 13Z tomorrow morning at all TAF sites.
A weak cold front will likely cause showers and thunderstorms
to develop in the afternoon 17-24Z. -SHRA with VCTS all TAF
sites for Tuesday afternoon.
Light south to southwest winds becoming mainly calm overnight.
Southwest winds of 10-15 knots on Tuesday.
Outlook...
Tuesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: Low Operational Impact. Slight Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. Slight Chance of SHRA...TSRA.
Friday Night: Low Operational Impact. Slight Chance of SHRA...TSRA.
Saturday: Moderate Operational Impact. Chance of SHRA...TSRA.
&&
.FIRE WEATHER...
Tonight will be warm and humid. Other than an isolated thunderstorm
over the southern Adirondacks, no rain is expected. Relative humidity
values will increase to 95 percent overnight.
Tuesday and Wednesday will be humid with a good chance of showers and
thunderstorms, with locally heavy rain possible each day. Relative
Humidity values will be mainly above 55 percent. Southwest winds will
be 5 to 10 mph on Tuesday and they will become westerly on Wednesday
around 5 mph.
&&
.HYDROLOGY...
A rather wet pattern over the last few weeks has allowed for
at least several inches of rainfall over much of the area. According
to the USGS, streamflows across the majority of the region are
above to much above normal. The exception is across the
Adirondacks and upper Mohawk Valley, where less rain has
occurred and river are levels are actually near or slightly
below normal.
Although dry weather is expected tonight, an approaching
frontal boundary will allow for some thunderstorms tomorrow and
Wednesday, with the greatest coverage during the afternoon and
evening hours. Locally heavy rainfall may accompany any
thunderstorm and the wet antecedent conditions and high stream
flows may easily result in some flooding, including the
potential for localized flash flooding. Urban, poor drainage and
low lying areas would be most vulnerable, especially within the
Capital Region. Rainfall amounts will be variable due to the
convective nature of the precipitation, but local amounts over
an inch are easily possible.
Dry weather may briefly return on Thursday, but additional
showers and thunderstorms are possible for Friday into the
weekend.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from noon to 9 PM EDT Tuesday for CTZ001-013.
NY...Heat Advisory from noon to 9 PM EDT Tuesday for NYZ038>041-043-
047>054-059>061-064>066-083-084.
MA...Heat Advisory from noon to 9 PM EDT Tuesday for MAZ001-025.
VT...Heat Advisory from noon to 9 PM EDT Tuesday for VTZ013-015.
&&
$$
SYNOPSIS...SND/MSE
NEAR TERM...SND/MSE/BGM
SHORT TERM...MSE
LONG TERM...ELH
AVIATION...SND
FIRE WEATHER...Frugis
HYDROLOGY...Frugis
Area Forecast Discussion
National Weather Service Caribou ME
1041 PM EDT Mon Aug 6 2018
.SYNOPSIS...
A weak cold front will slowly approach from the west tonight and
stall over the area Tuesday into Wednesday. High pressure will build
over the area Thursday. Another cold front will cross the region
late Thursday night followed by high pressure on Friday.
&&
.NEAR TERM /THROUGH TUESDAY/...
1035 PM Update...Things have quieted down w/the loss of
heating. The latest run of the HRRR in conjunction w/the
Canadian GEM seemed to be in line w/the radar was showing
showers apchg the western border. Stayed w/the daycrew`s
thinking of isolated showers affecting portions of the w and nw
overnight. The 00z RAP soundings indicated the potential for
some isolated convection as CAPE is forecast to be around 1000
joules and weak shear. Moisture is limited however to 700mbs and
above. Therefore, leaned away from adding thunder for the
overnight period.
It will be another very humid night and w/the partial
clearing and rainfall in sections of northern Maine, patchy fog
is expected. Temps have dropped into the 70s and will drop a bit
more overnight before leveling off, especially across western
areas as clouds move in. Adjustments were made to the hrly
temps/dewpoints to fit the latest conditions.
Previous Discussion...
A pre-frontal trough and a weakening shortwave will produce
isolated thunderstorms north of a line from Greenville towards
Houlton early this evening. These storms will provide enough
moisture to generate some patchy fog later tonight north of
Houlton. Otherwise, expect a warm and humid night with lows near
70F. The cold front will arrive Tuesday with a stronger upper
level shortwave than today and PWs will be approaching 2 inches
again. The forecast area remains in a marginal SPC risk area
with winds and heavy downpours being the primary threats. Shear
will be increasing tomorrow...providing better storm
organization rather than the pop-up cells observed this
afternoon. The deep moisture, slow moving front and potential
for training cells means some areas could receive locally heavy
rainfall of 1 to 2 inches within 3 hours or less. In terms of
the heat, the early arrival of frontal clouds is expected to
reduce highs to the 80s in Aroostook County, but low 90s are
again forecast south of Millinocket and heat index values may
briefly hit advisory criteria again.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A weak cold front will be stalled across the area Tuesday night as a
very weak shortwave approaches. Some thunderstorms may continue to
be along, and just south of the front over Downeast areas early
Tuesday evening. Otherwise, a small surface low forming in southern
areas will likely produce some showers, mostly Downeast, Tuesday
night. This first small low will slide east and away early on
Wednesday. Another weak low will ripple along the front late
Wednesday into Wednesday night bringing another chance of showers
with some isolated thunderstorms. Showers will be possible across
the entire area although Downeast, near the track of the low, will
be favored. Wednesday nights low has a better defined, though weak,
upper level shortwave approaching from the west southwest. Lift
ahead of this wave will support showers and the weak surface low
overnight Wednesday night. The front and weak shortwave low
will slide east and away on Thursday as a weak shortwave ridge
and surface high pressure follow to bring a return of partial
sunshine on Thursday.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Another cold front will approach Thursday night although this one
has very little moisture with it. However, this front is the leading
edge of some cooler air from Canada that will push across the north
on Friday bringing slightly drier air to our region, mainly across
the north. The high will crest over the state Friday night bringing
a calm and comfortable night. Our focus then turns to another
shortwave lifting north from the Mid-Atlantic region ahead of a
trough digging into the midwest. This low will bring increasing
clouds Saturday morning with a chance of rain late Saturday into
Saturday night. Current guidance is again favoring Downeast and
central areas while just brushing the very far north with rain. The
system is expected to progress through quickly, sliding east on
Sunday with clearing to follow late Sunday into Sunday night. Dry
weather should follow for Monday.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: Isolated thunderstorms are possible into this
evening north of GNR and HUL. Patchy fog is expected to cause
VLIFR vis north of HUL after midnight tonight. Fog will burn off
early Tuesday, but a cold front will bring thunderstorms from
Quebec by midday. These thunderstorms could produce wind gusts
over 40 mph and heavy rainfall. The front will slowly move
towards the coast by evening.
SHORT TERM: MVFR conditions in variable low clouds are expected
Tuesday night into early Wednesday. Conditions should improve
to VFR north early Wednesday and remain VFR to MVFR Downeast.
MVFR conditions north and IFR conditions Downeast in lower
clouds and some rain are expected Wednesday night into early
Thursday. Conditions should improve to VFR across the area by
midday Thursday as clouds and showers move away. VFR conditions
are expected through Friday.
&&
.MARINE...
NEAR TERM: Seas will slowly increase towards 3 feet due to a
long period south swell. Otherwise, fog is expected to return
tonight...mostly offshore...and retreat again Tuesday morning.
SHORT TERM: Winds and seas are expected to remain below SCA
Tuesday night through Saturday. Humid air over the colder water
will likely result in Fog Tuesday night into Thursday with a
possible improvement in visibility late Thursday into Friday as
high pressure builds across the area.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...Hewitt
Area Forecast Discussion
National Weather Service Cleveland OH
819 PM EDT Mon Aug 6 2018
.SYNOPSIS...
High pressure over the mid Atlantic states will weaken and
allow a cold front will move east into the region late tonight.
The front will stall across in the area Tuesday. Low pressure
will move east across Ohio along the boundary Wednesday. Weak
high pressure will build in for Thursday.
&&
.NEAR TERM /THROUGH TUESDAY/...
Front has not made much progress but activity is filling in along
the boundary from Detroit southwest towards Toledo and continuing SW
across Indiana. Will expect the more robust convection to the
west to favor a more southeasterly trajectory where a reservoir
of 3000 J/kg of CAPE remains. Less instability is present to
the east but expect showers with at least scattered
thunderstorms to continue eastward across the area overnight as
the front sinks southward. Main change with the update was to
raise pops in NW Ohio. Can not rule out a severe storm yet
through 11 PM but chances will continue to decrease with the
loss of daytime heating.
Previous discussion...
Radar shows isolated convection now along the lake breeze east
of KCLE and nothing much more across northern OH or nwrn PA. To
our west however convection across southern lower MI is moving
east. The HRRR looks to be having trouble with this so
confidence in its evolution is low. Movement is primarily east
however if the line develops further south it would time into or
at least near KTOL by around 5pm. A severe thunderstorm watch
is just to our west. Capes feeding into the line of storms are
between 2K and 4K J/kg would would expect storms to be
energetic as they move in. The HRRR may have a better handle on
subsequent convection which it develops to our west/northwest
and moves in after 00Z affecting most if not all locations
through the night. Will have likely pops most places with cat
pops northwest. Tuesday would expect showers and thunderstorms
to redevelop as a cold front drifts in from the northwest,
eventually stalling across the area or just to our southeast.
Models bring a short wave east across the region Tuesday night.
With moisture remaining in place will have chance pops for the
evening increasing to likely overnight with the best energy.
Highs Tuesday low to mid 80s.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A somewhat active latter half of the week begins Wednesday with
a cold front draped across the area in the morning, moving east
out of the area by the afternoon. Opted for minor changes to
pops during the day, pushing the likely pops a bit further east
, but have retained mid/high chance pops for most of the area
with some reinforcing mid level energy pushing across the area
Wednesday. Surface high pressure will regain control across the
region Wednesday night into Thursday, and have opted for a dry
forecast Wednesday night through Thursday morning, although a
piece of mid level energy tracking southeast through the
southern Great Lakes may bring a stray shower Thursday morning
into the afternoon. A stronger cold front will push south
through the Great Lakes Thursday settling close to the region
Thursday night and moving into the area on Friday. Pops increase
from Thursday afternoon through Friday from north to south
across the area, with the highest pops on Friday in the mid/high
chance range. Kept temps close to previous forecast, leaning
towards consensus MOS vs. raw guidance. The warmest day on
Thursday could see highs in the mid 80s across the area.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
Model trends are similar but still some doubt as to the timing
of systems in the Long Term Forecast. Both models have low
pressure system centered over Lake Erie by daybreak Saturday.
After that models diverge. GFS pushes low SE of forecast area
Saturday night, then it lifts north over the area again by
daybreak Monday. ECMWF on the other hand moves the low east of
the forecast area Saturday night then moves next system over the
area late Sunday into Monday. Best chance for convection
sometime Friday night into Saturday. Timing still in doubt so
went scattered -tsra both periods. Kept Saturday night into
Sunday dry then low chance pops from Sunday night into Monday.
Temps should remain near normal.
&&
.AVIATION /00Z Tuesday THROUGH Saturday/...
Showers and thunderstorms will continue to develop along a slow
moving frontal boundary extending from near Chicago to Toledo at
00Z. Thunderstorms have decreased in intensity but can not rule out
a few wind gusts to 40 knots or possibly stronger, mainly at NW Ohio
sites through 03Z. Brief heavy rainfall with IFR visibilities also
possible. The trend will be for thunderstorms activity to settle
south with time across TOL and FDY, with rain and scattered
thunderstorms continuing east across the other terminals through
10Z. A lull in activity is expected towards morning with scattered
activity filling back in on Tuesday afternoon. Conditions will
generally be VFR outside of thunderstorms although some MVFR
visibilities possible in the 09-13Z window. MVFR cigs also possible
on Tuesday in the morning with diurnal heating. Winds will be
Southerly ahead of the front, shifting to west or northwest
behind it on Tuesday.
OUTLOOK...Non-VFR possible with patchy morning BR. Non-VFR
likely in thunderstorms Tuesday afternoon through Wednesday.
&&
.MARINE...
Quiet conditions expected on the lake through the rest of the
week as high pressure remains centered south of the lake as a
cold front slowly approaches from the northwest. The front will
move across the lake Tuesday night into Wednesday, with
southwest winds becoming northwest behind the front. Winds will
quickly return to west/southwest flow by Thursday as high
pressure builds back across the lake. Another stronger cold
front will push south across the lake on Friday with winds
becoming northerly. Winds through the period will generally be
10 kts or less.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...TK
NEAR TERM...KEC/TK
SHORT TERM...Greenawalt
LONG TERM...DJB
AVIATION...KEC
MARINE...Greenawalt
Area Forecast Discussion
National Weather Service Hastings NE
1052 PM CDT Mon Aug 6 2018
.UPDATE...
Issued at 1048 PM CDT Mon Aug 6 2018
Updated the forecast to increase chances of preciptation and
change orientation of highest POPs farther north, then gradually
sag southeast overnight.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 336 PM CDT Mon Aug 6 2018
Aloft: Complex low-amplitude/zonal flow was over the Nrn USA per
RAP analyses...12Z upr-air data and satellite loops. A trof
extended from Hudson Bay back to UT...with multiple other smaller
embedded trofs. One such trof extended from the Neb Sandhills back
into Nrn CO. This trof will move across the CWA early this eve
while a stronger trof (currently over MT) slides SE toward the
Cntrl Plns as well. This trof will cross SD tonight with its tail
end brushing Neb/KS. Amplification of the flow will begin tonight
with cyclonic NW flow tomorrow.
Surface: A weak cool front was along the Neb/KS border this AM
and has been slowly sinking S thru the day. By 00Z this front
should be near I-70. The approaching trof will drive this front
further S into KS tonight. High pres was currently over the Nrn
Rckys. This high will weaken and slide SE behind the front into
Neb/KS tomorrow.
Rest of this afternoon: a few shwrs/tstms will be possible at any
time. We saw sct shwrs and a few tstms develop early. There
clearly isn`t much CIN. Can`t rule out a couple of tstms turning
svr...espcly after 4 PM. Attm it doesn`t look like coverage will
be that great. The main show looks like tonight.
MLCAPE from the 09Z SREF is fcst around 1250 J/kg N of I-80...
maximizing around 2000 J/kg over N-cntrl KS. 0-6 km shear will be
at least 30 kt.
Tonight: In the 9-11 PM time-frame we should see an appreciable
increase in tstms somewhere along or S of I-80 per multiple CAMs
in the 12Z HREF. These storms could be oriented WSW-ENE...
resulting in some heftier rain totals. Movement should be to the
SE...and these storms could be joined by others fcst to form over
CO and move across KS. Would not be surprised to see some 3" rain
amts due to cell training or persistence from the same location
being affected by more than 1 storm. Some localized flooding or
flash flooding might occur.
Another possible scenario is the tstm activity currently over NW
Neb consolidates and moves SE into the CWA...and it merges with
burgeoning development mentioned above. This per the 12Z HRRR
ensemble.
Some storms could be svr.
Tstms will exit SE of the CWA by dawn at the latest.
Fog: it could be a problem for the Tue AM commute. Dwpts remain
in the upr 60s-lwr 70s...and conds will be ideal for radiating...
away from the cirrus canopy that will develop from tonight`s
storms. That means the greatest risk for fog will be N of Hwy
6...and given how far lows will be below the cross-over
temp...would not be surprised if the fog is dense (1/4 mi or
less).
Tue: Fog (possibly dense) to start over S-cntrl Neb. Probably
m/cldy over N-cntrl KS. Once the fog dissipates mid-late
AM...should be very nice with m/sunny skies. Should see some CU
form with daytime heating.
.LONG TERM...(Tuesday night through Monday)
Issued at 336 PM CDT Mon Aug 6 2018
Aloft: The flow will become highly amplified as the cut-off low
(currently over the E Pac) approaches the W coast late wk. This
will force height rises and ridging over the Wrn USA with a trof
downstream over the E. This will maintain NW-N flow over the CWA.
By next weekend...the Pac low will open up into a trof and move
into the Pac NW...forcing the ridge to narrow and tilt over the
Plns. A cut-off low is fcst to develop over the OH Vly preventing
the ridge from moving E.
Surface: The pres grad will be weak the next svrl days with svrl
weak highs moving thru. The tail end of a very wk cool front will
move sag into Neb Thu and KS Fri. It will have little impact other
than to temporarily shift the wind dir. By this wknd...a large
high will develop over Ern Canada and the GtLks...and its Wrn
fringe will extend back into the Cntrl Plns.
Temps: will average near normal.
Rain: Not looking good. There will be a lot of subsidence. Most
areas will see little to none. A couple small chances did creep
back into the fcst in a couple time periods...but wouldn`t bet on
it panning out. Certainly nothing appreciable is currently
envisioned.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday)
Issued at 1048 PM CDT Mon Aug 6 2018
Main issue includes visibility as temperatures approach dewpoints
overnight and early Tuesday. May be an IFR/LIFR ceiling as well,
but too early to tell as of now. Most convection will slide
southeast of the terminals by 03Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
UPDATE...Heinlein
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Goodland KS
712 PM MDT Mon Aug 6 2018
.UPDATE...
Issued at 700 PM MDT Mon Aug 6 2018
Overview: Westerly flow aloft will prevail through tonight. A
potent shortwave located invof Rapid City SD at 00Z will track
E/ESE to Sioux City by 12Z Tue. In the lower levels, a SW-NE
oriented SFC-H85 thermal/moisture boundary extended from Johnson
City--Garden City--Hill City.
00-04Z: Radar trends, SPC mesoanalysis data, observations, etc.
suggest that the relative best potential for isolated severe
thunderstorms this evening will largely be confined to eastern CO
and southwest NE. In particular, a long- lived supercell tracking
SSE through western NE (approaching Ogallala at 0030Z) could
impact portions of Hitchcock/Red Willow counties in the 04-05Z
time frame. Whether or not this updraft will persist for several
more hours is difficult to ascertain, though the downstream
environment appears more than supportive (7.5C/km H7-H5 LR, 2500
MLCAPE, 40-50 KT EBWD).
04-12Z: Simulated reflectivity forecasts from the HRRR and NAM
NEST suggest that convection will develop over northwest KS
between 03-06Z and gradually progress E-SE into central/southern
KS between 06-12Z. With plentiful moisture (PWATs 1.3" to 1.5"),
moderate to strong instability (2000-3000 J/kg MUCAPE), and
strengthening low-level warm advection/frontogenesis invof the
H85 thermal/moisture boundary after sunset, the aforementioned
scenario appears quite reasonable. Updrafts developing invof the
SFC-H85 TMB in northwest KS are likely to interfere with one
another as coverage increases late this evening, however, with
moderate instability and effective deep layer shear on the order
35-45 knots, a few instances of large hail will be possible in
association with the more robust updrafts (or transient
supercells) during the 04-08Z time frame. Otherwise, the primary
hazard associated with post- sunset convection will be heavy
rainfall /isold flash flooding/, particularly invof the SFC-H85
TMB (along/east of Hwy 83).
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 247 PM MDT Mon Aug 6 2018
Main concerns for the short term period are potentially severe
storms this evening and fog overnight.
Currently, KGLD is showing some precipitation echoes in the
eastern half of the CWA. Expecting shower activity to increase
from the eastern Colorado / Kansas border. SPC has since backed
off on the severity of the majority of the CWA, but some cells
could still become severe this evening. If the cooler stable
airmass that`s moved over the area can get sufficient heating, we
may see multiple rounds of supercellular clusters bringing
damaging winds and large hail. Upslope flow will help aid in
supercells training and will help to pose flash flooding risks.
Target area will be the extreme southwestern half of our CWA
around the Colorado/Kansas line. Effective bulk shear values are
expected to be in the 40 to 50 knot range around peak afternoon
heating. SFC CAPE will be sitting in the 2500 to 3000 range, so
expecting large growth for the cells that do break the cap
creating potentially large hail. DCAPE values are lower than the past
couple of days, but it`s still sitting around 1000 this afternoon
which will be more than enough to bump winds to severe criteria.
Today`s highs are still on track, despite the impact of light to
moderate showers impacting the eastern half of the CWA. Tonight`s
lows may vary lower than previously forecasted by 5 to 10 degrees
across the Tri-State area depending on extent of showers tonight
and where the gradient sets up in relation to the prevailing
cooler prefrontal airmass. Expecting mid 50s to low 60s.
Overnight, winds are expected to relax and become light and
variable across the Tri-State area. This, in conjunction with the
cooler moist airmass, will allow radiation fog to develop.
Confidence on extent and timing is still a little uncertain, but
hanging on to persistence from this morning`s fog event for the
northeastern portion of our CWA to drop again, since it is even
more favorable tonight.
Tomorrow, expecting seasonably average highs in the mid 80s with
slight chances of precipitation in the evening.
.LONG TERM...(Tuesday night through Monday)
Issued at 303 PM MDT Mon Aug 6 2018
Main forecast issue will be for thunderstorm chances from Tuesday
night into Thursday night. Satellite showing an amplified pattern
from the eastern Pacific into western North America. Pattern is
being dominated at this time by large cutoff low off the Pacific
northwest. Broad troughing/faster westerly flow is over the eastern
portion.
Tuesday night...Area will be in easterly upslope flow at the
surface. Right rear quadrant of the jet will affect the south and
southwest third of the area through the night. At 500 mb there is
shortwave trough that moves through in northwest flow aloft. However
at 700 mb there is actually a shortwave ridge in place.
Looks like thunderstorms develop over the higher terrain to the west
of our area. Question becomes how far east does that cluster of
thunderstorms get. Mean wind is 5 to 10 knots and starts out north
and turns to the west. Per the reasoning above will keep the
thunderstorms confined to the western portion of the area and that
fits with the blend. The threat will have to watch for is locally
heavy rainfall. Precipitable water values are not as high before but
could get some decent rainfall amounts out of this.
Wednesday/Wednesday night...There looks to be linger rainfall in the
morning. Weak right rear quadrant moves across the area during the
afternoon and evening hours. Shortwave trough moves through in the
north to northwest flow aloft. There looks to be a rather strong Eml
in place and am wondering how much can develop. For now I am siding
with being slightly wetter than the output. Per the above reasoning
above and collaboration with neighbors, will insert slight chance at
this time.
Thursday/Thursday night...Weak right rear quadrant affect the
northern area Thursday afternoon and the entire area through the
night. At the same time, a shortwave trough moves through in
northerly flow. Forecaster builder gave me some slight chance pops,
and considering the weak lift those seem reasonable and will keep.
Temperatures look reasonable.
Friday through Monday...Models in good agreement through the period.
Amplified ridge is over the western portion of the area at the
beginning with north to northwest flow in place through Friday. Then
the ridge gets shoved slowly east as it becomes positively tilted
from the desert southwest into the north central portion of the
country. This is the result of trough off the Pacific Northwest
coast moving east and deamplifying.
For Friday and Friday night...Heights continue to slowly rise and
the flow becomes more northeasterly. This flow aloft usually means
much drier air and that is shown well by the output. Temperatures
are rather cool for this time of year. There is a weak shortwave
trough coming through. However considering the weak lift and rather
deep dry layer, am fine with a dry forecast.
For the remainder of the period. Ridge stays in about the same place
through this time with anomalous northeast flow aloft. This continue
to bring very dry air aloft with continue shortwave troughs in this
flow. Most of this period looks dry with a small chance possible on
Monday. Different/tricky flow that will just have to watch closely
for any subtle changes that could bring precipitation. Again what
the forecaster builder gave me looks reasonable and will keep.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 545 PM MDT Mon Aug 6 2018
Scattered thunderstorms are expected to develop over the Tri-State
area this evening/tonight. Either terminal could be affected, with
the relative best chance expected between 03-06Z at MCK and
03-08Z at GLD. MVFR conditions associated with stratus or fog
cannot be ruled out between 10-14Z (AOA sunrise) at either
terminal, though confidence is too low to warrant explicit mention
with the 00Z TAF issuance. Otherwise, expect VFR conditions and
light (5-10 knot) E/NE winds to prevail.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...VINCENT
SHORT TERM...EV
LONG TERM...BULLER
AVIATION...VINCENT
Area Forecast Discussion
National Weather Service Louisville KY
1009 PM EDT Mon Aug 6 2018
.Forecast Update...
Issued at 1009 PM EDT Mon Aug 6 2018
The forecast is in good shape. A line of thunderstorms has erupted
from Lake Erie to central Illinois along a cold front. The storms
will sag southeastward but will weaken as they become outflow
dominant, move away from the front, and the low level inflow
weakens. Still, widely scattered showers and storms should make it
into southern Indiana during the pre-dawn hours and into north
central Kentucky around sunrise, and are accounted for in the
forecast.
&&
.Short Term...(This evening through Tuesday)
Issued at 225 PM EDT Mon Aug 6 2018
A surface analysis this afternoon showed high pressure over the
southeast US with a weak area of low pressure over southeastern Iowa
and a warm front across northern Illinois and Indiana. Steady
southwesterly flow ahead of that feature over the lower Ohio Valley
has continued the very warm and humid conditions. Early afternoon
readings are in the upper 80s to lower 90s. GOES-East total
precipitable water values are between 1.7 and 1.8 inches and visible
satellite imagery shows pockets of towering cu. Convective
temperatures were being met and with the unstable environment in
place characterized by MLCAPE of 2000-2500 J/kg, isolated to
scattered showers have popped up.
Expect isolated to scattered thunderstorms to develop through
mid/late afternoon. HRRR and SPC HREF show greater coverage to be
across central KY into the Bluegrass region but pretty much anywhere
could see a pulse shower or storm. With DCAPE values of around 800-
1000 J/kg, any stronger storm would be capable of producing isolated
gusty winds along with torrential downpours.
A lull in activity is expected mid to late evening but convection is
likely to initiate northwest of the forecast area (IL/west central
IN) and may drop into southern Indiana after midnight through the
pre-dawn hours. This could set up an outflow boundary for tomorrow
and be the focus of convection but also could play into how much
heating/destabilization occurs by afternoon. If morning showers or
clouds hang around, this could limit how much instability builds.
Nonetheless, there`s good agreement and clustering in 12z SPC HREF
reflectivity ensembles for scattered to numerous convection across
the area. 12z run of the NAM/GFS show better shear (still not overly
impressive) but this should result in better storm organization. SPC
Day 2 outlook continues to highlight marginal risk of severe storms
along/north of the Ohio River.
.Long Term...(Tuesday night through Monday)
Issued at 200 PM EDT Mon Aug 6 2018
Slow-moving cold front will be sparking off showers/storms Tuesday
night and continuing into Wednesday as the lagging upper trough
crosses the Ohio Valley. Wind fields do not look overly strong in
the low levels, but there should be good lift in the right rear quad
of a jet streak over central IL to MI Tuesday night. The NAM has
another streak coming in from the west could enhance lift Wednesday
afternoon as well.
The front won`t make it far south, and with another wave crossing
the region Thursday, at least south Kentucky will keep rain chances
in for the day. Looking beyond, upper trough looks to stall
somewhere in our vicinity, keeping temperatures a little below
normal, along with better rain chances across the region into this
weekend. Individual impulses rotating around this feature are hard
to time this far out, but the effect will be to bring in above-
normal rain chances.
&&
.Aviation...(00Z TAF Issuance)
Issued at 744 PM EDT Mon Aug 6 2018
Afternoon convection has diminished with the lack of a trigger and
the loss of heating. Therefore, expect a quiet rest of the evening
and much of the overnight. Will be watching for a scattered line of
showers and storms ahead of a cold front to drop toward HNB/SDF/LEX
in the pre- and post- dawn hours. Will continue mention of Prob30
for this time frame. Assuming this early morning convection doesn`t
completely stabilize the atmosphere, expect a second round of
scattered to numerous showers and storms in the afternoon hours at
all sites. Expect a general light SW wind through this TAF cycle
ahead of the front.
It is also worth noting that fog formation should be mitigated by
mid/upper sky cover moving in toward dawn and light but somewhat
mixy surface winds.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13
Short Term...ZT
Long Term...RJS
Aviation...BJS/JMB
Area Forecast Discussion
National Weather Service Pueblo CO
919 PM MDT Mon Aug 6 2018
.UPDATE...
Issued at 918 PM MDT Mon Aug 6 2018
Extended SVR Watch 333 across the southeast plains through 04z.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 229 PM MDT Mon Aug 6 2018
Precipitable water (PW) values over the eastern plains today are
and inch and higher, with less than an inch over western areas.
Low level upslope flow over eastern areas will continue into the
evening and could help sustain convection along the eastern mtns.
Models agree and have been consistent in showing widespread tstms
moving acrs the southeast plains through the evening as an upper
level disturbance moves acrs the area. Western area are expected
to mainly have isolated to scattered showers/tstms. NAM and GFS
show the upper disturbance moving out of the area in the late
evening, with decreasing convection acrs the plains from west to
east. However the latest HRRR is showing another line of storms
moving into the northern portions of El Paso county around 06Z
tonight and then continuing southeastward acrs the plains. Not
sure if this will happen, but we`ll have to monitor how things
develop.
The main concerns for this evening are the potential for flooding
on burn scars that are over and near the eastern mtns, and the
potential for severe weather over the plains. Storms will have
the potential to produce heavy rain over the mtns and plains this
afternoon and evening, and this will be a risk particularly if it
occurs over burn scars or urban areas. The NAM is forecasting
CAPE values over 2000 J/kg acrs the plains this afternoon and
evening, with bulk shear values of 40-50 kts. SPC has a slight
risk of severe over southeast CO. The main risks are large hail
and damaging wind gusts, but an isolated tornado or two cannot be
ruled out.
For late tonight, the forecast models show some light lingering
precip chances over the plains, and possibly some of the eastern
mtns.
Conditions on Tue are expected to be similar to today. Another upper
disturbance is forecast to move over eastern CO, but it may be
exiting the area by late afternoon or early evening. Forecast models
show storms mostly developing after noon, and then mainly being over
and near the eastern mtns and the Palmer Dvd and El Paso county, and
the Raton Ridge, with storms not moving over the eastern plains
until evening. PW values over eastern areas remain high on Tue and
low level upslope flow continues. Afternoon CAPE are again expected
to be over 2000 J/kg with 40-50 kts of shear, and once again SPC has
eastern areas in a marginal risk for severe weather.
.LONG TERM...(Tuesday night through Monday)
Issued at 229 PM MDT Mon Aug 6 2018
Ensembles spreads are low through the extended period with higher
confidence in the overall forecast. Operational solutions are
also similar through the extended period, with wet conditions
early in the period, with drier conditions late this week into the
weekend.
Tuesday night through Wednesday...high pressure will be centered
over the western states with shortwaves dropping south across
Colorado. The first will be moving southeast across Eastern
Colorado Tuesday night. Heavy rain and thunderstorms will likely be
ongoing, initially along the Eastern Mountains, spreading east across
the Plains Tuesday night into Wednesday morning. Flash flooding
will remain a threat, especially on area burn scars. There is also
a small severe threat across the Plains with large hail and strong
winds being the primary threats. On Wednesday, expect another round
of heavy rainfall due to showers and thunderstorms. Outflow from
the previous nights convection will turn flow upslope easterly
across the Plains. This will help convection develop over the
Eastern Mountains, and spread southeast through the evening hours. A
few strong to severe storms are possible across the Eastern Plains
during the evening hours. Flash flooding will remain a threat on
area burn scars and areas that see heavier rainfall Tuesday.
Thursday through Monday...high pressure will shift northeast through
early next week forcing flow across the region northeasterly. Drier
air will also work across the area. Heavier showers and
thunderstorms will remain possible over the mountains on Thursday.
As we move into Friday into Monday, shower and thunderstorm activity
will become more isolated to scattered in nature. They will also
become more diurnally and terrain driven. Given the northeasterly
flow aloft, the thunderstorm activity will shift southwest into New
Mexico during the evening to overnight hours.
Temperatures are expected to remain warm across the region.
Afternoon highs will generally be in the mid 80s to lower 90s, with
the warmest conditions beyond Thursday. Overnight lows will
continue to be mild with upper 50s to mid 60s. Mozley
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 229 PM MDT Mon Aug 6 2018
There will be a good chance for showers and thunderstorms at KCOS
and KPUB thru at least early this evening. Heavy rain could
reduce the visibility. Late tonight there could also be some low
clouds at KCOS and KPUB creating MVFR conditions. KALS is
expected to have VFR conditions thru the next 24 hrs, however
easterly low level winds tonight, could bring some moisture to the
area and the potential for some low clouds late tonight and early
Tue. Another round of thunderstorms is expected Tue afternoon and
evening at KPUB and KCOS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until midnight MDT tonight for COZ072>075-
079>081-087-088.
&&
$$
UPDATE...MW
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...28