Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/03/19
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1037 PM EDT Fri Aug 2 2019
.SYNOPSIS...
Northern areas will be fair and chilly tonight, while southern
areas will see an increase in cloudiness, with a chance of a
shower or thunderstorm. Isolated to scattered showers and
thunderstorms are expected from the Capital District and to the
south and east Saturday mainly during the afternoon into the
early evening hours. Fair and seasonable weather is expected for
Sunday and Monday.
&&
.NEAR TERM /THROUGH SATURDAY/...
Updated at 1030 pm. Mid-to-upper level wave moving northeast
from Pa and western NY is easily identified by satellite imagery
late this evening. Cloud top temperatures have begun to warm
with this system as of late this evening and radar loops have
shown a clear weakening trend with convection that had been over
central NY eariler in the evening. Latest CAMS including the
00z HRRR and NAM nest all indicate isolated to scattered
coverage of showers moving east toward our area overnight with
chc pops implied across much of the area by around 12z. Showers
and storms may become heavier and a bit more widespread by early
afternoon, especially to the south and east of Albany as the
tail end of the wave interacts with an atmosphere destabilizing
due to diurnal heating. Previous discussion is below.
Updated at 8 pm. Mid-to-upper level wave associated with height
falls and scattered showers over Pa and south central NY will
move slowly east across the area through Saturday morning. The
wave will bring scattered showers to our area, especially south
of I-90 where weak southerly flow ahead of the wave will bring
dew points back into the mid to upper 60s overnight. Showers
will likely diminish in coverage for awhile late this evening
with the loss of daytime heating, but should increase again
toward daybreak Saturday as the wave approaches. A few rumbles
of thunder could occur with any heavier showers later tonight as
modest instability is forecast to persist through the night.
Clouds will increase overnight, with lows ranging from the 50s
in the Adirondacks, to the 60s elsewhere.
As of 407 PM EDT, mostly sunny skies continue, except across
the southern third of the forecast area where skies have become
partly cloudy with cumulus bubbling up. Temperatures range from
the 70s in the hill towns to low to mid 80s in the valleys.
dewpoints are generally in the 50s with 40s across the southern
Adirondacks. Winds are variable at 10 MPH or less. Weak
shortwave over Ohio is producing showers and thunderstorms from
the southern tier of New York, across Pennsylvania, to southern
NJ and the Delmarva Peninsula. Expect showers to our southwest
to slowly move northeast tonight while dissipating. Have slight
chance to chance POPs over eastern Catskills.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
The surface high will shift off the southern New England coast
tonight leading to a developing southerly flow. This southerly
flow will advect moisture from the mid Atlantic States northeast
ward into our area. There are showers and thunderstorms now
over southern tier of New York and northeastern Pennsylvania,
and these will move slowly northeast tonight while dissipating.
Have included slight chance to chance POPS over southern areas
for showers and isolated thunder. Tonight will not be as cool
across the southern part of the area with clouds overspreading
like a blanket. However, the southern Adirondacks, lake George
area and souther Vermont will not see as much cloudiness, and
have dewpoints in the 40s this afternoon, so they may see low
temperatures around 50 with some upper 40s possible.
It will be more humid on Saturday and a cold front will
approach the region from the north. Heights will fall across
the region and dew points are expected to rise into the 60s
across much of the area with upper 60s into the mid Hudson
Valley and northwestern Connecticut. Guidance is consistent
indicating convection should fire up from Capital District and
to the south and east where the greater instability will be with
the higher dew points. Expecting isolated to scattered storms
mainly during the afternoon into the early evening hours. The
storms are expected to weaken and dissipate with loss of
daytime heating. Expecting highs once again in the 80s with mid
and upper 70s occurring above 1500 feet.
The cold front will drop south across the region Saturday night
and with its passage drier air will begin to filter in on a light
northerly flow. Low chance POPs for additional showers with the
cold front. Expecting lows in the mid 50s north to mid 60s south.
On Sunday morning, the front may be pushing through the eastern
Catskills, mid Hudson Valley and NW Connecticut. For now, slight
chance POPs over easter Catskills for a Sunday morning shower.
Expecting fair weather will lower dew points, more comfortable
humidity levels and a nice northerly breeze. Temperatures
expected to be cooler especially across the higher terrain of
the southern Adirondacks and southern Green Mountains. Looking
at highs in the lower to mid 80s up the Hudson River Valley and
northwestern Connecticut with 70s above 1000 feet in the higher
terrain of the southern Adirondacks and southern Green
Mountains.
High pressure will shift across the region Sunday night. It
will be cooler with lows down in the 50s with 40s in the
normally cold spots of the southern Adirondacks, southern
Vermont and possible Berkshire County MA as well.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Fair and seasonable conditions to start the forecast period,
followed be unsettled conditions for Tuesday-Friday, as a large
upper level trough slowly digs across eastern Canada and the Great
Lakes region.
High pressure should allow for fair conditions Monday, with warm
daytime temps in the lower/mid 80s in valleys, 70s across higher
terrain areas, and seasonably cool nighttime lows in the 50s to
lower 60s, with some upper 40s possible across portions of the
southern Adirondacks and southern VT.
As the aforementioned trough initially digs into the Great Lakes
region, a surface front approaching from the west should bring
increasing chances for showers and thunderstorms Tuesday into
Wednesday, with best chances associated just ahead of the front
and/or with any pre-frontal boundaries. It will be warm and more
humid ahead of the front, with highs mainly in the 80s for valleys,
75-80 across higher elevations. Overnight lows may be somewhat
elevated due to cloud cover and higher humidity levels, with mainly
60s for lower elevations, and 55-60 across higher terrain.
For Thursday into Friday, weather becomes a bit more nebulous,
depending on how far south and east additional shortwave energy
rotates around the deepening upper level trough. Showers and
thunderstorms will be mainly diurnally driven during this time
period, further enhanced with the approach/passage of any stronger
upper level impulses. Temperatures Thursday-Friday may be a bit
cooler due to more clouds, some showers and colder air aloft, with
highs mainly in the mid 70s to lower 80s, and overnight lows in the
50s to lower 60s.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
An isolated shower over Ulster county early this evening will
likely weaken and is not expected to affect the POU TAF site.
VFR conditions will continue through most of the night, however
increasing amounts of moisture may bring some MVFR cigs and
vsbys toward daybreak especially at POU and PSF. Scattered
showers will also develop across the area late tonight and
continue into Saturday as increasing moisture interacts with a
weak upper-level wave of low pressure moving east across the
area. Some stronger thunderstorms may develop Saturday
afternoon with the best chance being at PSF/POU. Winds will be
variable at speeds less than 10 kts through Saturday, except
stronger near any thunderstorms Saturday afternoon.
Outlook...
Saturday Night: No Operational Impact. NO SIG WX. Sunday: No
Operational Impact. NO SIG WX. Sunday Night: No Operational
Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX. Tuesday:
Moderate Operational Impact. Chance of SHRA...TSRA
&&
.FIRE WEATHER...
Northern areas will be fair and chilly tonight, while southern
areas will see an increase in cloudiness, with a chance of a
shower or thunderstorm. Isolated to scattered showers and
thunderstorms are expected from the Capital District and to the
south and east Saturday mainly during the afternoon into the
early evening hours. Fair and seasonable weather is expected for
Sunday and Monday.
Maximum relative humidity values tonight are forecast to be 85
to 100 percent. Minimum values Saturday will be in the mid 40s
to mid 50s. Saturday night RH recovers again to 85 to 100
percent.
&&
.HYDROLOGY...
Isolated to scattered showers and thunderstorms are expected
from the Capital District and to the south and east Saturday
mainly during the afternoon. Fair weather is expected for the
second half of the weekend and to start the new work week. The
weather will then turn unsettled beginning on Tuesday as low
pressure approaches and moves across the region. Any
thunderstorm will be capable of producing locally heavy
downpours. River flooding is not anticipated at this time.
Please visit our Advanced Hydrologic Prediction Service /AHPS/
web page for specific area rivers and lakes observations and
forecasts.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...SND
NEAR TERM...SND/MSE
SHORT TERM...SND
LONG TERM...KL
AVIATION...MSE
FIRE WEATHER...SND
HYDROLOGY...SND
Area Forecast Discussion
National Weather Service Charleston SC
1026 PM EDT Fri Aug 2 2019
.SYNOPSIS...
A weak coastal trough will persist through Saturday before
dissipating. A front will then stall near the area early next
week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Late this evening: No change to the forecast thinking for the
rest of the night. However, the last few runs of the HRRR and
RAP are now taking the offshore wave, and the main area of
showers and thunderstorms associated with it, just a bit further
offshore. The result is that these newer runs would now keep
most land areas dry. On the other hand the new NAM still puts
quite a bit of activity along and just inland of the coast. With
the late evening update the highest rain chances have been
shifted a bit further east, but it will be a close call for
where showers and thunderstorms set up. That will be the main
forecast challenge overnight.
Early this evening: There wasn`t much convection this afternoon
across the forecast area as cloud cover and morning rainfall
prevented much, if any, destabilization. However, we are
situated within a very moist airmass with precipitable water
values on the order of 2-2.2 inches, and the onshore flow around
the nearby surface trough is producing enough convergence for
showers to develop along the Georgia coast. Through the evening
and the rest of the overnight, models are in pretty good
agreement showing a weak surface wave off the east coast of
Florida pushing northward into the waters of the forecast area.
As it does, showers and thunderstorms are expected to increase
in coverage over the waters and then begin to rotate toward the
coast and push inland. Rain chances steadily increase in this
manner, with the best chance for rain to occur as we approach
sunrise and through the mid morning along the South Carolina
coast. Overall, the rain chances we had in place look good and
no significant changes were made. Fortunately, it looks like the
peak of showers and thunderstorms will be well after the high
tide tonight, so that should lessen any freshwater flooding
concerns.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
A coastal trough will slowly move northeast along the coast on
Saturday. Scattered to numerous showers along with a few
thunderstorms are expected during the day, especially across
southern SC and coastal GA. PWATs will be above 2.2" along
coastal areas, thus locally heavy rainfall will be possible.
On Sunday the surface trough will pull away from the area,
however a weak upper trough lingering to the west will still
allow for at least scattered showers and tstms.
The upper trough will drift to the east on Monday, pushing a
weak surface front toward the area. Moderate instability and a
moist airmass will support scattered to numerous showers and
tstms, especially in the afternoon.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Mid-level troughing will persist over the East Coast. At the
surface, weak troughing will prevail inland while high pressure
is over the Atlantic. Expect the typical afternoon
showers/thunderstorms with seasonal temperatures.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
A tricky forecast period is on tap through 00z Sunday. At KCHS,
VFR conditions are expected to prevail through the evening. Then
around after midnight, the chance for showers and thunderstorms
goes up as well as the potential for MVFR or lower ceilings.
Overall, the worst conditions are expected generally in the
09-15z time frame. We introduce prevailing MVFR ceilings at 05z,
lowering them close to IFR by 09z. Confidence is too low in IFR
at this point to include in the forecast. Thunder is certainly
possible, and has been included in a TEMPO group from 10-13z.
After mid-morning, overall confidence is low but we expect there
to be a lull in shower and thunderstorm activity with a general
improvement in conditions with VFR returning by early afternoon.
At KSAV, MVFR ceilings are already impacting the terminal,
though probably on a TEMPO basis this evening. Then late
tonight, rain chances increase as showers and thunderstorms
develop offshore and attempt to push onshore. Have timed
prevailing MVFR ceilings in at 04z with showers. Could see a
period of IFR ceilings closer to sunrise, but confidence is too
low to include at this time. Expecting improving conditions by
late morning with a return to VFR by midday or early afternoon.
Extended Aviation Outlook: Occasional ceiling and/or visibility
restrictions are possible due to showers and tstms.
&&
.MARINE...
Tonight: Mainly east winds, shifting to more southeast late, as
a trough approaches from the south. Speeds should peak in the
10-15 kt range with seas up to 4 ft, highest near the Gulf
Stream.
Friday through Tuesday: Atlantic high pressure will remain the
dominant feature Saturday through the middle of next week, along
with a few weak surface troughs meandering through the waters.
No headlines are expected.
&&
.TIDES/COASTAL FLOODING...
Tides are reaching their peak now and will fall just shy of
warning criteria at both Charleston Harbor and Fort Pulaski.
Will leave the warning up until tides fall below 7 ft and 9.2 ft
respectively.
The combination of astronomical and meteorological influences
will continue to generate elevated tides this weekend. The
Saturday evening high tide is forecasted to reach Coastal Flood
Advisory levels for the entire coast while the Sunday evening
high tide may reach Coastal Flood Advisory levels for only the
Southeast SC coast. Additionally, if heavy rainfall occurs
around the time of high tide, this will exacerbate the flooding,
especially for the Charleston Peninsula.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Coastal Flood Warning until 1 AM EDT Saturday for GAZ117-119-
139-141.
SC...Coastal Flood Warning until 1 AM EDT Saturday for SCZ048>051.
Coastal Flood Advisory until 1 AM EDT Saturday for SCZ052.
MARINE...None.
&&
$$
NEAR TERM...BSH
SHORT TERM...JRL
LONG TERM...MS
AVIATION...BSH/JRL
MARINE...RJB/JRL
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Duluth MN
628 PM CDT Fri Aug 2 2019
.SHORT TERM...(This evening through Saturday night)
Issued at 304 PM CDT Fri Aug 2 2019
A stalled out frontal boundary was located along the
International Border early this afternoon with high pressure in
place to the south of Lake Superior. Isolated to scattered showers
and thunderstorms were seen across northeast Minnesota and this
activity is expected to continue for the remainder of the
afternoon hours before diminishing during the early evening hours.
Storms have been firing in an uncapped airmass characterized by
1000-2000 J/kg of CAPE and shear under 15 knots. These storms
have been pulse-y in nature and one cell near Silver Bay featured
nickel-sized hail. Given the lack of shear, expecting that nickels
will be about the best these storms can do. Winds through the
column are also extremely weak, so not expecting much in wind
gusts from the storms either. Used the HRRR to highlight slightly
higher POPs this afternoon along with observational trends. This
activity is expected to drift southeast into this evening with dry
conditions expected for the overnight hours as lows cool into the
middle 50s to middle 60s.
The boundary will remain in the area for tomorrow, leading to
another afternoon of isolated to scattered showers and
thunderstorms. Without an organized mechanism for convergence, it
is difficult to try and hone in on an area that will see the best
chance Saturday afternoon. Since today`s plan with the lake breeze
leading to initial convection and outflow boundaries thereafter is
not really panning out, opted to blanket the area with low POPs
and let later shifts refine this area based on satellite, radar
and CAM trends. Conditions look virtually the same for tomorrow
with 1000-2000 J/kg of CAPE along with shear under 20 knots. This
will lead to pulse-type airmass storms that may produce sub-severe
hail and heavy rainfall, but not much else. This activity will
again be diurnally driven, so a weakening trend is expected during
the early evening hours leaving dry conditions for overnight.
Highs Saturday will top out in the middle 70s to middle 80s with
lows in the middle 50s to middle 60s.
.LONG TERM...(Sunday through Friday)
Issued at 304 PM CDT Fri Aug 2 2019
Sunday through Monday we have a cold front that slowly slides
through the area, which is associated with an upper level low and
trough axis that moves through Manitoba and into Ontario through
this period. The better dynamics will be north of the the
Northland, but we are still looking at a period of chances for
showers and thunderstorms both days, focused mainly along and ahead
of the front as it moves through the area. High temperatures on
Sunday to remain in the 80s, but then as the front moves through, it
will become cooler on Monday, with highs only in upper 70s to low
80s, at least in part due to increased cloud cover. The upper low
will still be in the vicinity on Tuesday, even as the cold front
shifts off to the southeast of the area. This will leave us with
some diurnally driven showers and thunderstorms in the cyclonic
flow, and am carrying some small chances for showers and storms,
mainly during the afternoon and evening hours. Temperatures to
remain on the cooler side, with highs in the mid to upper 70s.
The latter half of the work week the upper level pattern keeps us in
northwest flow aloft, with the upper low from earlier in the week
over Hudson Bay or even Quebec, and a ridge over the Rockies. This
will produce some small chances for showers and thunderstorms with
weak shortwaves sliding through that flow, but have poor confidence
in the timing and track of such shortwaves and have kept pops to
slight chance or lower through Friday. Temperatures should be a
little cooler than normal, but not unusual for this time of year,
with highs Wednesday through Friday in the 70s for most locations.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 629 PM CDT Fri Aug 2 2019
As isolated showers and storms dissipate early this evening across
northeast Minnesota and northwest Wisconsin, skies will at least
partially clear out, especially at HIB and INL. Fog is expected to
develop, possibly reducing visibility to less than a mile at DLH
and HIB towards Saturday morning. On Saturday, fog will burn off
by mid-morning with VFR conditions expected to prevail through the
day with a mix of sun and clouds. Isolated showers and storms are
again possible, but left out any mention of precip in this set of
TAFs due to very low confidence in whether any terminal may see
precipitation. Winds very light at around 5 knots or less and
variable in direction through the forecast period, nearly calm at
times overnight.
&&
.MARINE...
Issued at 304 PM CDT Fri Aug 2 2019
Scattered thunderstorms over the area this afternoon will continue
to move out over Lake Superior, and bring locally higher winds and
waves, along with some lightning and small hail with the stronger
storms. Otherwise, southwest to west winds today near or less than
10 knots are expected to turn to the northeast late tonight or early
Saturday, and slowly increase through the day. These winds may
increase to around 15 knots in the southwest arm of the lake in this
northeast flow, and depending on gusts we may need a small craft
advisory for a few hours in the afternoon. The east to northeast
winds are expected to continue into Sunday, but generally remain
less than 10 knots.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 61 80 59 84 / 40 40 10 20
INL 58 85 62 84 / 10 30 10 50
BRD 62 84 63 85 / 10 30 0 20
HYR 60 84 59 84 / 20 30 10 10
ASX 61 80 59 86 / 40 20 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...BJH
LONG TERM...LE
AVIATION...JJM
MARINE...LE
Area Forecast Discussion
National Weather Service Hastings NE
725 PM CDT Fri Aug 2 2019
.SHORT TERM...(This evening through Saturday)
Issued at 353 PM CDT Fri Aug 2 2019
Aloft: Upr-air data from RAOBs and aircraft and RAP tropopause
analyses showed that the flow over the CONUS was dominated by a
large subtropical high over NM with a ridge extending into the
Canadian Prairies. Trofs were along the Pac NW coast and along the
Appalachians. Anticyclonic NW flow was over NEB/KS. A wk mid-lvl
shrtwv trof extended from ND-KS. This trof will diminish further
as rounds the high into the lwr MS Vly by 00Z/Sun.
Surface: High pres was over the GtLks. A barely noticeable
stationary front extended acrs the Gulf Coast states to wk low
pres along the KS-OK border. Another wk low was over SD. This low
will dissipate tonight while the KS-OK low gradually sinks into
Nrn TX by 00Z/Sun. Meanwhile...the wk GtLks high will gradually
shift to the W and extend into NEB.
Rest of this afternoon: Partly to mostly cldy. The mdls hv been
struggling with the nebulous forcing. The main concern on this
shift has been the persistent low-echo-centroid convection
affecting Valley county with flash flooding. The echoes hv been
very persistent. 88D estimates pockets of 4-8" may hv occurred. We
won`t know for sure until the gauge reports come in. We hv
received reports of water over county roads.
PWAT is around 2". These are incredibly efficient rainers with
warm rain processes dominating.
Can`t rule out isold shwrs popping up elsewhere...but despite the
lack of a cap...the lack of forcing may keep much from happening
outside of what`s already in progress.
Tonight: Partly cldy during the eve. Can`t rule out isold shwrs
and possibly a tstm or two. Somewhat begrudgingly left a mention
of precip in the fcst...but believe most locations should remain
dry. Conds are fvrbl for fog and low stratus to reform. MAV MOS
has been insistent for the last 5 runs that widespread fog will
form with vsbys in some areas 1/4 mi or less. We may need to issue
a Dense Fog Advy.
Sat: A foggy start for most if not all the area. It could be
dense. Skies should eventually become partly cldy...but as it
erodes from the edges...there could be a swath that remains mostly
cldy for much of the day.
Did maintain a mention of precip...but it will probably be dry.
.LONG TERM...(Saturday night through Friday)
Issued at 353 PM CDT Fri Aug 2 2019
Aloft: Moderately-amplified anticyclonic NW flow Sun will
deamplify Mon as a fairly potent low mvs thru the Canadian
Prairies. This will cause heights to fall and cyclonic WNW flow
over NEB/KS as the subtropical high gets suppressed and shoved
back into the W a bit. The flow will become less cyclonic mid-late
next wk...but remain from the WNW.
Surface: A cool front associated with the Canadian Prairies low
will move thru Mon. Another cool front is fcst to mv thru Thu. In
the interim...wk high pres.
Temps: averaging a little cooler than normal.
Pcpn: Isold tstms will be psbl Mon with the FROPA. Thereafter...
the mdls are suggesting isold tstms here and there...but
predictability and confidence are extremely low. Overall...the
chance of rain is not good. Most locations will remain dry.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 719 PM CDT Fri Aug 2 2019
Significant wx: IFR CIGs/VSBYs likely.
Tonight: Mixed VFR/MVFR/IFR conditions next few hrs, with VFR/MVFR
the most prominent through 04Z. CIGs will deteriorate around 06Z
with eventually some fog developing by 09Z, which will probably
fall to 1/2 to 1 mi through dawn. Winds will be lgt out of the ESE
before going lgt and vrbl late. Confidence: CIGs - high, VSBYs -
medium.
Saturday: IFR to MVFR. IFR CIGs/VSBYs expected to start the day
with gradual improvement by mid to late morning. Should see primarily
MVFR CIGs for the aftn, but VFR isn`t out of the question. Winds
will be SE around 5-10kt. Confidence: Medium.
&&
.HYDROLOGY...
Issued at 353 PM CDT Fri Aug 2 2019
We need to watch the N Loup Rvr Basin as svrl inches of rain fell
this aftn. That water will be working its way down thru Valley/
Greeley/Howard counties. Water lvls will be rising for sure. We
may need to issue Areal Flood Wrngs for the N Loup Rvr and the
creeks that drain into it.
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Thies
Area Forecast Discussion
National Weather Service Paducah KY
747 PM CDT Fri Aug 2 2019
.UPDATE...
Issued at 744 PM CDT Fri Aug 2 2019
Updated the public forecast to add in some isolated showers and
thunderstorms in a few locations for the next couple of hours.
Recent HRRR data indicates that the convection moving west from
Bowling Green Kentucky will eventually spread back into our
Pennyrile counties before dissipating late this evening. Also a
rogue shower has developed out of an area of agitated cu in
Hamilton county Illinois. A few more will be possible in the zone
roughly from Carmi to Mt Vernon Illinois in the next hour or two.
UPDATE Issued at 616 PM CDT Fri Aug 2 2019
The AVIATION section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 232 PM CDT Fri Aug 2 2019
Surface high pressure centered over Lake Michigan this afternoon is
ever so slowly losing its grip on the region. The result is an
increase in cumulus clouds and an uptick in humidity levels, at
least across the eastern half of the region. A few very isolated
showers briefly popped up in Todd County Kentucky early this
afternoon. A small chance for isolated convection will remain
possible this afternoon over western Kentucky.
Guidance has come into better agreement depicting an uptick in
convection for Saturday afternoon. This looks to be mainly across
the southern half of the region, coinciding with an increase in low
to mid level moisture associated with weak energy in the broad
trough across the southeast U.S. Overall coverage should still be
rather low though.
Slight chance PoPs remain in place mainly across western Kentucky on
Sunday, as the better moisture appears to get shoved a little
further south.
Temperatures remain seasonably warm in the upper 80s for highs and
upper 60s for lows through the weekend.
.LONG TERM...(Monday through Friday)
Issued at 232 PM CDT Fri Aug 2 2019
The medium range models and the GEFS/ECENS appeared to be in
reasonable agreement for the extended forecast period, with finer
details a bit harder to pin down. The country will continue to be
under a persistent ridge west/trof east mid/upper pattern. This will
keep the PAH forecast area under northwesterly flow aloft through
the period. At this time, the first half of next week appears drier
than the second half in the models.
One of the more persistent signals for possible pcpn will be
sometime in the middle of next week, associated with one or more
shortwave impulses embedded in the increasingly cyclonic northern
stream flow. The presence of this energy should result in some mid
level height falls in our region as the western ridge is nudged
westward. A weak surface reflection (cold front) may approach as
early as Tue. The initialization blend yielded Tue night as a peak
time for PoPs (but generally no more than a 1 out of 3 chance),
fading off to the east on Wed. The next pcpn signal appeared to be
on Day 7 (Fri) when possible MCS activity may get going in the
northern Plains and head southeastward into our region. The general
forecast of limited probability of showers and tstms will probably
hold, however the timing and intensity of activity next week will
remain quite changeable.
While surface dewpoints should stay in the range of 65 to 70 across
the region, high temps should start out around 90, with lows around
70. The latter half of the week is forecast to be cooler by just a
few degrees at most.
&&
.AVIATION...
Issued at 616 PM CDT Fri Aug 2 2019
It appears that the isolated showers over west Kentucky have given
up for the evening. Clear and nearly calm conditions may lead to
some fog development late tonight. As has been the case lately,
KMVN will have the greatest chance at fog late tonight, and cannot
rule out more IFR or lower conditions with mainly MIFG. Not sure
about KCGI. Based on cross-over temperatures they should not
repeat the MVFR fog from this morning.
Guidance advertises a return of lower clouds from the south late
tonight into Saturday morning. Any ceilings should be VFR, but a
brief MVFR ceiling cannot be ruled out at KCGI from midday through
mid-afternoon with a rather thick cu field expected. Isolated
SHRA/TSRA will be possible again in the afternoon, but expected
coverage is too low to mention in the forecasts as this time.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DRS
SHORT TERM...SP
LONG TERM...DB
AVIATION...DRS
Area Forecast Discussion
National Weather Service Blacksburg VA
1153 PM EDT Fri Aug 2 2019
.SYNOPSIS...
An old frontal boundary will combine with upper level disturbances
to generate showers and thunderstorms across the Appalachians and
central mid Atlantic region into the weekend. The boundary will
continue to weaken and erode Sunday through Tuesday.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 845 PM EDT Friday...
Convection has been much less this evening with most of the
area in an area of relative weak instability on the cool side of
the surface front along the far southeast periphery of the CWA.
However have seen a few showers/storms develop near the
boundary across the piedmont where likely tripped off via a
passing outflow boundary seen on radar. These again not moving
much and expect may see added development off outflow past dark
espcly given a weak axis of instability over eastern sections
and moisture convergence to the south. Latest short term models
tend to fade these showers out shortly, while some including the
latest HRRR show redevelopment of shra/tsra back toward the
Blue Ridge/Roanoke through midnight within the light easterly
flow. Therefore keeping in some low pops across eastern/southern
sections for another few hours before cutting to mainly
fog/stratus during the early morning hours given combo of
clearing and weak upslope flow. Lows mainly in the 60s again per
dewpoints in the moist 60s to lower 70s this evening.
Previous update as of 640 PM EDT Friday...
Sent a quick update to lower pops espcly across central sections
where seeing little in the way of showers given only weak
instability and support aloft. Also edged down coverage over the
far west where have been worked over with mainly chance coverage
for now elsewhere through the evening. Also lowered temps some
in the southwest per cooling from heavier downpours from late
this afternoon. Otrw just some other adjusts for clouds and to
cut back on QPF this evening given less shower coverage than
earlier expected.
Previous discussion as of 318 PM EDT Friday...
An upper trough axis will remain across the Appalachians this
afternoon into Saturday. The combination of mid-level vorts, solar
heating, orographic lift and low level boundaries will create
scattered showers and thunderstorms this afternoon into tonight. The
SPC mesoscale analysis at 18z indicated CAPEs from 1000-2000 J/KG
and sfc based LIs around minus 2 to minus 4. The namnest, hrrr and
HiResW-arw-east showed the best chance for convection along the
southern mountains. Some of storms could contain heavy rain with
precipitable water values in the 1.5 to 2.0 inch range and light
steering flow. Cell mergers or outflow boundary enhancement may help
intensify storms. An isolated strong to severe pulse thunderstorm is
possible with damaging winds and hail. Decided not to post any flash
flood watch because of forecasted limited coverage of heavy rains.
Flash Flood guidance was below 2 inches in portions of western
Greenbrier County, from parts of the New River Valley down into
Smyth and Tazewell Counties, and around Lynchburg. Elsewhere FFG was
fairly high above 2 inches.
Areas of low clouds and fog will develop tonight into Saturday
morning. Low temperatures tonight will range from the upper 50s in
the mountains to upper 60s in the piedmont.
Upper level troughiness will continue across our region on Saturday.
Scattered showers and thunderstorms will form Saturday afternoon
into Saturday evening. The Day 2 Convective Outlook keep us in
general thunderstorms. There is no real change in the airmass
expect for the mid-level temperatures being a touch warmer. High
temperatures on Saturday will vary from the lower 70s in the
mountains to the mid 80s in the piedmont.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 318 PM EDT Friday...
Broad trough remains in place, though airmass remains virtually
unchanged. Front situated south of us, but a series of upper
shortwaves will keep threat of showers and thunderstorms going into
Monday, with the best chance during the afternoon/evenings.
Temps still running close to normal for early August.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 220 PM EDT Friday...
Broad trough appears to amplify somewhat midweek pushing a cold
front across our area Thursday. Appears a lull in convection as high
pressure overhead, though airmass remains sub-tropical so not out of
the question to have isolated storms. Better forcing arrives Wed-Thu
as the front approaches with 5h heights falling. The models differ
on how far south the front gets, but appears could see drier/lower
humidity toward Friday.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
As of 650 PM EDT Friday...
VFR conditions with localized MVFR/IFR possible in areas of low
clouds and scattered convection this evening. Coverage of any
lingering showers and thunderstorms will then diminish after
sunset with areas of lower clouds and fog developing overnight.
Some solutions hang onto added showers along the Blue Ridge
overnight but too iffy to include mention attm. Ceilings will
be lowering to IFR/MVFR across the area after midnight. Areas of
fog will develop overnight especially in the valleys, as well
as locations that received afternoon rainfall, and perhaps along
the Blue Ridge per easterly flow. KLWB has the best chance for
LIFR/IFR fog overnight into Saturday morning.
Morning low clouds and fog will lift by afternoon return most
locations to VFR conditions although low clouds/fog may hang in
across eastern sections until midday. Widely scattered showers
and thunderstorms will develop Saturday afternoon resulting in
brief sub-VFR, but appear too sporadic to include mention in
any of the Taf locations for now.
.Extended Aviation Discussion...
A weak boundary will remain close to the region through
the end of the weekend. Scattered showers and thunderstorms
with periods of sub-VFR ceilings can be expected through Sunday
or Monday with coverage becoming less by Tuesday. This pattern
will also result in MVFR or lower clouds and MVFR fog due to
moist low levels, especially at night. Showers and thunderstorms
may develop again Wednesday with the best chances in the
northwest.
&&
.EQUIPMENT...
The NOAA weather radio at Lynchburg VA remains off the air
tonight perhaps due to a surge with a lightning strike Thursday
night. Technicians will continue to work to find the problem
over the next couple of days although the time of restoration
is unknown at this point.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/KK
NEAR TERM...JH/KK
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/JH/KK
EQUIPMENT...JH