Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/31/18
Area Forecast Discussion
National Weather Service Wakefield VA
1000 PM EDT Thu Aug 30 2018
.SYNOPSIS...
High pressure will remain anchored well off the Mid Atlantic and
Southeast coast overnight through Sunday. A weakening frontal
boundary will linger across portions of the area into Saturday,
before washing out.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 958 PM EDT Thursday...
Early evening analysis reveals a wavy, and increasingly diffuse
sfc cool front draped across the Atlantic coast from Long
Island, across the DelMarVa coast and extending W-SW across the
VA/NC border back into W VA/KY.
Sct to numerous convection...primarily sub-severe but with a few
stronger cells...continues to slowly wane with loss of heating
this evening. Storms popped up quickly earlier this evening,
pooling along upper level trough axis to the west, with slow-
moving storms persisting along Theta-E ridge in place and
bisecting the area this evening, bringing localized heavy rain
and several reports of nearly continuous lightning to the area.
Activity will hang on over the next couple of hours per Time-
Lagged HRRR (which has handled activity well thus far). Modified
PoPs slightly to show convection dropping off in areal coverage
overnight as it slides to the ENE twd the VA nrn neck and Lower
MD ern shore into the overnight hours, with silent PoPs into
Fri morning. have included some patchy fog wording out west with
partial clearing and light winds. Otherwise, mostly clear to
partly cloudy tonight with lows ranging thru the 70s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
As of 345 PM EDT Thursday...
Not as hot but still humid Fri thru Sun. With the boundary
lingering over portions of the area, continued chcs for showers
and tstms (20-50%) will prevail, mainly during the aftn/evening
hours. Highs on Fri, Sat and Sun generally 85-90F. Lows mainly
in the lower to mid 70s thru the period.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 345 PM EDT Thursday...
A 500hPa anticyclone builds back into the region by Monday, and is
forecast to remain over the eastern third of the country for much of
next week. The anticyclone will be centered over OH/PA/NY/NJ from
Tue-Thu as it slowly strengthens. This will put much of VA/NC in
(weak) easterly flow aloft. At the surface, high pressure will be
anchored offshore for much of next week. While the core of the
highest H85 temperatures (18-20C) will be N/NW of the region, expect
more of the same conditions to continue. Afternoon highs will range
from the upper 80s to lower 90s with lows between 70 and 75 degrees
for much of next week. Isolated afternoon/evening showers and
thunderstorms will be possible throughout the extended period, with
the highest coverage over the Piedmont. Capped PoPs at 30% given
that the coverage of showers/t-storms will be relatively sparse.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
As of 745 PM EDT Thursday...
As of 745 PM, there is a cluster of t-storms stretching from
the eastern Piedmont to just west of RIC. Expect this area of
t-storms to propagate to the east before slowly weakening from
now through 06z. T-storms will likely impact RIC from 00-03z, so
included a TEMPO group to account for this. Not as confident
about t-storms at the other terminals, so left VCSH in the TAFs
for now. May need to amend if it becomes clear that t-storms
will impact a given terminal. Regardless, expect brief IFR/LIFR
flight restrictions due to +RA in any storm. Mainly VFR
conditions after 06z tonight, with the exception of some patchy
fog late tonight, mainly from RIC westward. Went ahead and added
some MVFR BR at RIC from 08-12z. Expect SCT-BKN CU around 4-5k
feet Friday afternoon, with isolated-scattered t-storms
possible.
Outlook...Chances for mainly isolated to scattered aftn/evening
showers and t-storms continue this weekend, due to instability
and lingering frontal boundaries.
&&
.MARINE...
As of 315 PM EDT Thursday...
Bermuda high pressure will remain in control of the weather
across the local marine area through at least the middle of next
week. A weak frontal boundary will linger over the area through this
evening, and then lift back N later tonight. Expect a SSW wind of 5-
15kt S of the boundary and N/NE 5-10kt to the N of the boundary. The
wind will generally become E-SE 5-10kt by Friday aftn, but locally
10-15kt N of Chincoteague as high pressure builds across New
England. The wind will become more sea-breeze (diurnally) driven
over the weekend with a S-SW ~10kt morning/overnight and SE
aftn/early evening. This pattern continues early next week as we
remain under the influence of high pressure. Seas will mainly be 2-
3ft, with ~1 foot waves and 1-2ft at the mouth of the Bay.
&&
.CLIMATE...
Temperature data from the Norfolk ASOS (ORF) has been
unrepresentative this month for high temperatures. Therefore,
the daily highs have been substituted with data from the nearby
co-op site (min temperatures have not been adjusted).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...TMG
NEAR TERM...MAM/TMG
SHORT TERM...ALB/TMG
LONG TERM...ERI
AVIATION...ERI/TMG
MARINE...AJZ
CLIMATE...
Area Forecast Discussion
National Weather Service Bismarck ND
1005 PM CDT Thu Aug 30 2018
.UPDATE...
Issued at 1001 PM CDT Thu Aug 30 2018
In addition to blending the latest observations with the
forecast, tweaked cloud cover over the next couple of hours based
on the latest satellite observations and high resolution guidance.
Also refined precipitation chances through 12z based on model
trends. No other changes for this update package.
UPDATE Issued at 634 PM CDT Thu Aug 30 2018
No major changes needed for this update. Did introduce a small
area of slight PoPs over the next couple hours where some
agitated CU has been bubbling along a pre-frontal surface trough.
While the trend has been for these clouds to dissipate, the HRRR
continues to develop a couple of storms along this boundary.
Therefore cannot completely rule the potential out. Otherwise,
just blended the latest observations with the forecast.
&&
.SHORT TERM...(This evening through Friday)
Issued at 232 PM CDT Thu Aug 30 2018
For the short term, a cold front across northwest North Dakota
through eastern Montana is forecast to move through the region
overnight. Ahead of the front, very warm afternoon temperatures
around 90 have been noted across southwest North Dakota, where
relative humidity as low as 15 percent is occurring.
This evening scattered showers are expected along the frontal
boundary as it progresses southeast. CAM models show the threat
for showers will spread from northwest into the central to the
southeast, where higher dewpoints may support an isolated
thunderstorm late tonight.
On Friday, cooler temperatures, in the 70s to around 80, are
forecast, with scattered morning showers and isolated
thunderstorms across the James River Valley.
.LONG TERM...(Friday night through Thursday)
Issued at 232 PM CDT Thu Aug 30 2018
Saturday will be dry and pleasant, with highs in the 70s to
around 80. Then expect a few showers or a thunderstorm Saturday
night, with mainly dry weather Sunday. Highs Sunday in the 70s.
As August ends and September begins the forecast will be fairly
typical for this time of the year. Highs for the week will be in
the 70s to around 80 and lows in the 40s and 50s. Widely
scattered showers are possible during the week, but little
rainfall expected.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 634 PM CDT Thu Aug 30 2018
VFR conditions are expected through the period. Breezy winds
across portions of the west should begin to relax as the sun sets
and a cold front continues to push across the state. Mid to high
clouds increase from the west behind the front tonight, bringing a
chance for showers across the west overnight.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ZH
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...ZH
Area Forecast Discussion
National Weather Service Caribou ME
1031 PM EDT Thu Aug 30 2018
.SYNOPSIS...
Cooler and drier air will move into the area through Friday as
Canadian high pressure builds southward. The high will move east
of the region on Saturday into Sunday.
&&
.NEAR TERM /THROUGH FRIDAY/...
1025 PM Update...The latest satl imagery showed clouds still
around in the western areas but further s and e, clouds had
dissipated w/clear skies. The latest RAP soundings showed the
clouds out west dissipating overnight. Winds dropping off
overnight and clear skies will allow temps to drop back into the
40s across the northern 1/2 of the CWA w/low 50s across the
central and downeast areas. Some sites in the nw areas could see
upper 30s by sunrise. Patchy river valley fog still look like a
good bet overnight.
Previous Discussion...
The cool air mass will modify slightly Friday, but highs will
only reach the low to mid 70s with light winds. There is H850
moisture that will result in some cu fields by later Friday
morning into the afternoon. Humidity will remain pleasantly low.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
A high pressure ridge will dominate the weather through the
short term period of the forecast. A bit cooler with highs in
the low to mid 70s and overnight lows in the lower to mid 50s
across the area on Saturday. Temperatures will be about 5
degrees warmer for both highs and lows for Sunday. A short wave
will track along the northern boundary of the high pressure
ridge bringing few scattered showers may move into northern
Maine before the end of the period.
Used a blend of GFS/ECMWF/NAM/GEM for max/min. skycon wind, and
hrly temps. Loaded WPC for QPF. Used GYX wind gust tool for
gusts.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
A cold front will be extended across northern Maine at the
start of the period bringing showers and scattered TSTMs to the
area. This frontal boundary will remain across the region
through Tuesday morning. It will move into the Gulf of Maine
Tuesday afternoon. A ridge will briefly build across the area.
The ridge will build east as the frontal boundary moves back
into the state as a warm front early Wednesday morning. This
frontal system will finally clear the area Thursday afternoon
and higher pressure will move into the area through the end of
the period.
Used a blend to smooth out differences in extended models . Used
GYX wind gust tool for gusts. Loaded NAWave 4 for seas in the
coastal waters.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: VFR conditions are forecast through Friday. Skies
will clear tonight. Some localized cigs around 5000ft are
expected by late morning Friday.
SHORT TERM: VFR conditions all sites through Sunday afternoon.
VFR conditions will continue for BGR, BHB, and HUL. VFR with
periods of MVFR conditions in shower Sunday afternoon in
showers. MVFR conditions will spread south to the BGR and BHB
region overnight Sunday. MVFR conditions will persist through
the end of the period.
&&
.MARINE...
NEAR TERM: No significant weather is expected. Seas will remain
below 3 feet. Winds will pick up later tonight with some gusts
reaching nearly 20 kts, but decrease again during Friday.
SHORT TERM: Winds and seas below SCA criteria through the
period.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...Hewitt
Area Forecast Discussion
National Weather Service Quad Cities IA IL
936 PM CDT Thu Aug 30 2018
.UPDATE...
Issued at 935 PM CDT Thu Aug 30 2018
Have updated the forecast to both lower pops and delay the onset
of the already low thunderstorm chances late tonight. Recent
trends show elevated moisture advection on a 30 to 40 kt low
level jet focusing on far northeast KS into SW IA and another axis
over far NW IA into SW MN. Convective allowing models and 00z RAP
and NAM models have associated convection breaking out in MN
into western IA roughly between 09z and 12z with the help of an
advancing weak shortwave over NE and SD. This activity would then
then move east to southeast, possibly reaching into southeast IA
and northeast MO mid to late morning. Some models indicate
strong to severe discrete cells as this complex as it is shown
latching onto the surface warm front over SE IA into NE MO mid to
late morning to keep an eye on.
With weak elevated thetae convergence possibly reaching into east
central and se IA toward 12z and steep mid level lapse rates,
cannot completely rule out at least isolated showers and
thunderstorms toward sunrise. However, at this rate, it looks most
of the forecast area will be dry overnight and further reduction
of pops may be needed.
&&
.SYNOPSIS...
Issued at 301 PM CDT Thu Aug 30 2018
At the surface, the area remains on the western periphery of high
pressure over the Great Lakes. With cool air aloft, and ample
surface moisture, stratocumulus and cumulus are forming in the
heat of the day. To the southwest, moisture return is ongoing west
of the high pressure.
&&
.SHORT TERM...(This Evening through Friday)
ISSUED AT 301 PM CDT Thu Aug 30 2018
While increasing chances for rain will be over the area late tonight
and Friday, the main thrust of heavy rain concerns are not until
Friday night and beyond. With diurnal clouds over the central and
northeast, skies will initially clear out this evening, allowing for
another cool night. The southwest, under mid clouds already and
increasing clouds through the night, will be warmer in the upper
60s. Rain chances appear late and tied to a waa band will be
lacking much upper support, thus I plan on keeping pops low in
coverage. Friday morning, mid level waa will help storms move east
as they dissipate. That may allow for coverage to increase through
mid morning, then decrease again. I have held highs down under the
cloud cover, but that still results in lower 80s in most spots.
By afternoon, more storms are possible. There is not expected to be
much surface CAPE nor convergence for surface based storms. Elevated
storms should not be supportive of much more than heavy downpours
until the LLJ supported storms form later on Friday night.
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 301 PM CDT Thu Aug 30 2018
The main forecast concerns continue to be chances of showers and
thunderstorms through the period. Models are in good agreement on
the overall pattern through Monday but the agreement quickly
breaks down after that. There are timing and placement of feature
issues through the period.
The 500 mb pattern is characterized by an active southwesterly
flow aloft through the weekend until the Bermuda High retrograde
into the southern Mid Atlantic states early next week causing a
steepening of the flow aloft across the Central Plains. This GFS
solution has a steeper southerly flow allowing for a tapping of
warm and moist Gulf of Mexico air through the remainder of the
first week of September while the ECMWF and Canadian have a steeper
southwesterly flow and the Gulf of Mexico air has a longer travel
time into the Upper Midwest. The GFS solution would be warmer and
more moist then the Canadian and ECMWF. Both solutions would
still amount to warmer than normal air and above average
precipitation. each forecast period has chances of precipitation
given the shortwave energy moving across the region. The timing of
each individual wave will be difficult until 24 to 48 hours ahead
of time.
The southwesterly flow aloft on Friday night into Saturday shows
3 distinct shortwaves moving across the region through the period
which could bring multiple rounds of showers and thunderstorms.
The models are in good agreement with 1.75 to 2.00 inches of
precipitable water so the energy will have more than enough
moisture availible and could bring some hydrology concerns for the
weekend.
The Storm Prediction Center has eastern Iowa in a slight risk of
severe thunderstorms with far southeastern Iowa, northwest
Illinois, and northeast Missouri in a Marginal Risk. The timing of
shortwave would be with waning surface based instability and 0 to
6 kilometer shear of 30 to 40 knots so severe thunderstorms are
possible in the evening on Friday night and again on Saturday with
a Marginal Risk across the entire area. Currently, the models have
the timing of the shortwave energy a little better during the
afternoon and early evening. The timing of both of these events as
well as the placement of any frontal boundaries in the area and
there effect in the environment. Please stat tuned for further
details.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 632 PM CDT Thu Aug 30 2018
A band of strato cumulus clouds along a developing warm front
will affect BRL with initial MVFR conditions this evening, but VFR
conditions are expected elsewhere. Scattered thunderstorms are
expected to move into the area Friday. While forecast confidence
with convective trends is low, these have been confined to a mid
to late morning timeframe, where storms appear more likely.
There is a potential for widespread MVFR clouds Friday, but
forecast confidence is low and thus conditions have been kept
prevailing VFR.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...Sheets
SYNOPSIS...Ervin
SHORT TERM...Ervin
LONG TERM...Cousins
AVIATION...Sheets
Area Forecast Discussion
National Weather Service Goodland KS
1005 PM MDT Thu Aug 30 2018
.UPDATE...
Issued at 948 PM MDT Thu Aug 30 2018
Just completed an update. 00z soundings, mesoanalysis, and latest
model data indicating that overnight thunderstorms will once again
be possible across our area. Some thunderstorms have developed to
our north. Model data hints that either this activity will
continue or die off then reform further east and south over our
areas.
DDC 00z and 700 mb forecasts show another shortwave and warm air
advection pattern with decent lapse rates and elevated Cape in
place. Possible that a weak right rear quadrant could be in place
as well. Also the cap looks to be the weakest in the east just in
advance of this setup. So inserted a slight chance in the eastern
portion of the area from later tonight into mid morning on Friday.
Considering the instability and lapse rates, a severe storm or two
cannot be ruled out.
&&
.SHORT TERM...(This evening through Friday Evening)
Issued at 123 PM MDT Thu Aug 30 2018
A primarily zonal flow exists in the upper-levels with the core of
the jet stream mainly confined to Canada and a secondary jet finger
streaming in over Southern California northeastward into Western
Iowa. The flow becomes more meridional as the jet finger curves more
southwesterly over Southern Arizona and curves back northeastward
over the tri-state area by the end of the period. This shift in the
upper-level pattern will encourage southwesterly flow will aid in
downslope flow throughout the latter portion of the forecast. This
will encourage temperatures to rise and reach into the 90s again by
late afternoon.
SPC has placed the Tri-State area under a marginal risk for severe
thunderstorm activity for Friday. Moisture accumulation has been
taking place for quite some time as the Bermuda High keeps a
steady stream of moisture moving into the Central Plains. Wedged
between two high pressure circulation centers, the pressure
gradient will remain fairly tight and encourage an 850 mb low
level jet. Subsequently, the theta-e gradient will continue to
recede northwestward placing CO/NE/KS in an area of increasingly
higher equivalent potential temperatures.
A weak cold front is approaching the area from the north and will
arrive by Saturday at 12Z then stall out and begin to transition to
stationary. Friday evening, convection is expected to begin sometime
between 18Z-00Z and persist throughout the end of the period,
becoming weaker during hours of diurnal cooling. The strongest
SBCape exists in the eastern sector, reaching 2800 j/kg by 18Z and
up to 3300 j/kg by 00Z. PW values remain upwards of 1", DCape tops
out at 1700 j/kg, and the highest 0-6 km bulk shear is 40 kt for
Friday afternoon/evening. The risks associated with these storms if
all parameters come together will be large hail, with the LHP
showing values of 20 in the NE corner of the area per the NAM, 14
per both RAP and GFS as well as damaging winds considering the
DCape.
.LONG TERM...(Saturday night through Thursday)
Issued at 1255 PM MDT Thu Aug 30 2018
Saturday night-Sunday night...showers and thunderstorms will be
possible Saturday night as upper level energy moves in ahead of a
broader upper trough that resides generally just to the west of the
area. For the far northeast and eastern forecast area moisture and
higher pops are oriented northeast to southwest which is parallel to
the flow aloft. Precipitable water is around 1.5 inches favoring
some locally heavy rainfall. Precipitation coverage decreases a bit
but moisture in the 850-500mb column remains highest across the east
where highest pops advertised Sunday. Another area may be over far
western Kit Carson and Cheyenne counties of Colorado. For Sunday
night precipitation chances continue as favorable moisture remains
under southwest flow aloft. Low temperatures both nights in the mid
50s to mid 60s. High temperatures Sunday in the upper 70s to low 80s.
Monday...precipitation chances slowly decrease in the afternoon with
dry weather generally expected during the night as the deeper
moisture moves away from the area. High temperatures in the upper
70s to low 80s. Low temperatures in the mid 50s to mid 60s.
Tuesday...850-500mb moisture is forecast by the GFS and GEM to lift
north into much of the area in between an upper low and its trough
across the west and upper high over the east coast. This will
provide another chance for showers and thunderstorms. High
temperatures in the low to mid 80s. Low temperatures again in the
mid 50s to mid 60s.
Wednesday-Thursday...weather pattern gets a little more messy thus a
low confidence forecast. Currently have chances for showers and
thunderstorms through the period. High temperatures both days in the
upper 70s to low 80s. Low temperatures Wednesday night in the mid
50s to mid 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 542 PM MDT Thu Aug 30 2018
For Kgld, vfr conditions are expected through the period. At this
time any fog or thunderstorms in the region will not affect the
site. Through the night the winds will gradually shift from the
southeast to the west at 7 knots. The winds will remain there
until late in the afternoon when they shift back to the southwest.
For Kmck, vfr conditions are expected through the period. Some
light fog of greater than 5 miles is expected from 11z to 15z.
Thunderstorms are not expected to affect the area.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...SANDERSON
LONG TERM...99
AVIATION...BULLER
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1046 PM EDT Thu Aug 30 2018
.SYNOPSIS...
A strong upper level ridge dominating the East Coast will
weaken through Friday, allowing a cold front to approach from the
north. The front is expected to stall just north of the area on
Friday. Then the upper ridge will build back over the eastern states
this weekend through early next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1030 PM: The last few HRRR runs have been insistent on
convective redevelopment along and near the I-77 corridor, and it
has indeed come to pass with lingering sbCAPE of 1000 to 1500 J/kg
in that area along with triggering from outflows. The coverage
should settle down in this area around midnight or shortly after,
but will keep at least isolated PoP going until 06Z in this area.
Elsewhere, coverage should remain relatively sparse through
midnight, with isolated to scattered thunderstorms slowly
dissipating into the early morning hours. Cannot rule out a few
showers overnight, especially in the southwest mountains, but
thunder should dwindle in the stabilizing airmass.
Otherwise, a weakness in the subtropical ridge will remain across
the area through Friday. This will permit weak short waves to cross
the area. The better forcing, instability, and moisture will be
across the mountains - where numerous coverage is expected again
Friday afternoon. However, there is enough instability for isolated
to low end scattered convection elsewhere. Isolated flooding will be
possible across the mountains and foothills with any training echoes
as the locally heavy rainfall redevelops on Friday afternoon. The
chance of organized severe storms is low. However, very high
piedmont DCAPE values will once again mean an isolated damaging wind
gust will be possible. Lows tonight will be a couple of degrees
above normal. Highs Friday will be cooler than Thursday, but still a
couple of degrees above normal.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 200 PM Thursday...A ridge of high pressure will build
across the Mid-Atlantic States over the weekend. The forecast area
will be on the south side of this feature allowing weak easterly
flow to develop across the area. This will lead to a very consistent
temperature pattern with highs near to a little above normal and
overnight lows several degrees above normal. Scattered mainly
diurnally driven showers and thunderstorms are expected each day
with the higher chance in the mountains.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 200 PM Thursday...The mid level ridge will strengthen across
the Mid-Atlantic and Ohio Valley through next week. The ridge will
develop slightly north leaving the forecast area under similar
conditions for the week as the short term period. A little above
normal late summer temperatures are expected with scattered mainly
afternoon showers and thunderstorms.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Convective redevelopment will impact KCLT
through 04Z, with activity likely waning quickly after midnight.
Otherwise, VCSH/VCTS will linger mainly around KHKY for a couple
more hours. The best chances of any restrictions overnight will be
in the mountain valleys again, but patchy MVFR fog is possible
elsewhere, especially where rain fell. Any restrictions will burn
off by mid-morning with cumulus developing by early afternoon. the
best chance of convection will again be across the mountains on
Friday afternoon, but will carry PROB30 for thunder throughout given
the instability. Expect light S to SW flow throughout - away from
any thunderstorms.
Outlook: Scattered diurnal showers and thunderstorms are expected
each afternoon Saturday through Tuesday. Areas of fog and low
stratus can also be expected each morning, primarily in the mtn
valleys.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 95% High 100% High 100%
KGSP High 100% High 95% High 100% High 100%
KAVL High 100% Low 39% High 100% High 100%
KHKY High 100% High 83% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 95% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...SW
NEAR TERM...HG
SHORT TERM...SW
LONG TERM...SW
AVIATION...HG
Area Forecast Discussion
National Weather Service Memphis TN
948 PM CDT Thu Aug 30 2018
.DISCUSSION...
The Mid-South is located in a weakness between the upper ridge
over Texas and another developing over the Atlantic seaboard.
Scattered to numerous showers and thunderstorms developed this
evening in this areas of lower heights and they continue to chew
up areas of unused unstable air. Most of the activity is now
confined to NW TN and areas along the TN River with a couple of
storms over parts of NE MS. There is also some leftover rain from
earlier storms across much of eastern AR. Outflow from those
earlier NE AR storms has pushed SE and set off a few more storms
over western Tipton/Lauderdale counties and further south near of
the Shelby/DeSoto County lines. This new activity combined with
the latest HRRR solution will necessitate at least small pops
after midnight across the Mid-South. Update already out.
SJM
&&
PREV DISCUSSION... /issued 329 PM CDT Thu Aug 30 2018/
At 3 PM CDT... A surface front is currently extended across the
region, roughly along the I-40 corridor. Showers and storms are
ongoing, primarily just south of this feature, and will likely
continue along and south of the feature throughout the evening
hours. A look at the latest observations reveals temperatures in
the mid to upper 80s, with clouds present over much of the area in
association with the front.
The front shows no signs of vacating the region by the end of the
week, bringing another chance for showers and thunderstorms mainly
across eastern and southern portions of the FA for Friday.
Temperatures will be a bit warmer for late week, with highs closer
to 90 on Friday. The latest mid level analysis depicts the region
sandwiched between two areas of upper ridging. As an upper trough
amplifies over the west by early in the weekend, the ridging will
become located more over the local area. This will result in
drier, albeit warmer conditions. Heat indices will be the
greatest concern for the holiday weekend, with values nearing 100
degrees for Saturday and Sunday.
By late weekend the region will be on the western periphery of an
upper ridge, with southerly flow at the surface. This will be
sufficient to provide moisture transport into the region to
support at least slight chance for POPs each afternoon. Other than
diurnal shower and thunderstorm activity, no widespread
precipitation is expected during the forecast period. Temperatures
will remain a bit warmer than normal for early September, with
daily highs near 90, and heat indices remaining near 100 degrees
for many locales.
ZDM
&&
.AVIATION...
00Z TAF cycle
Mainly VFR conditions should continue for much of the forecast
period. Some scattered thunderstorms remain over portions of the
forecast area and this activity will continue to diminish through
the early evening hours. Some low clouds and areas of fog are
possible during the overnight hours. More thunderstorms are
possible Friday afternoon mainly over eastern sections of the
forecast area. Winds are expected to be variable tonight at around
5 knots and then become more southeast at 5 to 10 knots on Friday.
ARS
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Paducah KY
930 PM CDT Thu Aug 30 2018
.UPDATE...
Issued at 930 PM CDT Thu Aug 30 2018
Updated the grids and forecast to reflect a more persistent chance
of convection overnight across southeast MO into west KY. The MO
convection seems to be with a small scale MCV with the activity in
TN moving NW on the periphery of the H7 ridge to our east. Both
are outflow driven as well. The HRRR has probably had/has the
best handle suggesting the activity basically merging across west
KY and part of SEMO. How much of the activity holds on overnight
is still a low confidence call. But given the HRRR, will keep
small chances going. -CN
&&
.SHORT TERM...(Tonight through Saturday night)
Issued at 222 PM CDT Thu Aug 30 2018
Mesoscale Convective System (MCS) continues to dive southeast
along instability gradient into northern AR/southern MO as of 2 pm
CDT. Have kept main focus for measurable precipitation and
thunderstorm activity limited to western sections of southeast
Missouri this afternoon and evening. There may be some remnant
low/mid-level vorticity to maintain isolated convection in the
western four (4) counties of southeast Missouri into the evening
hours. Do not anticipate much convection overnight. Any convection
over the southern Pennyrile, north of the frontal boundary, should
dissipate with sunset.
Preference toward the Canadian, ECMWF, and to a lesser extent the
GFS Friday through Saturday. The mean ridge axis sets up from
southwest to northeast across the WFO PAH forecast area, with
slightly better moisture advection over the Pennyrile region of
west Kentucky Friday and Saturday afternoons. Have low forecast
confidence that this precipitation will develop, but maintained
for collaboration purposes and any slight shifting of the ridge
axis westward. The lack of significant cloud cover, insolation
should bring maximum temperatures back to near normal, in the
upper 80s.
.LONG TERM...(Sunday through Thursday)
Issued at 222 PM CDT Thu Aug 30 2018
High pressure aloft over the mid Atlantic strengthens across the
Eastern Seaboard and mid Ohio river valley thru the course of the
long term portion of the forecast. This will keep our pool of
temps and dew points where they have been, near 90 for highs, near
70 for lows, with almost uniform dew points in the lower 70s thru
the duration.
The best chance for relief from this continuation of summer thru the
Labor Day Holiday and into the first work week of September will be
mainly the heat of the afternoon/instability shower or storm that
could bubble up. However, with the strong subsidence, this will be
an isolated to widely scattered chance at best.
&&
.AVIATION...
Issued at 625 PM CDT Thu Aug 30 2018
All convection has remained south of the TAFs sites for now. Will
monitor for any northward development through the evening. Winds
will remain relatively light through the period, ranging between
40 to 170 degrees through the forecast period. Cloud cover should
be VFR for the evening and overnight periods. Will watch for the
development of any fog at KCGI as well. Diurnal cu will form
Friday afternoon.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
Area Forecast Discussion
National Weather Service Pocatello ID
949 PM MDT Thu Aug 30 2018
.UPDATE...Updated the forecast to add lingering light showers and
isolated thunderstorms over the Southeast, Eastern and Upper Snake
Highlands for this evening. Little rain, if any, is expected.
Convective outflow winds of 20 to 30 mph are possible. TW
&&
.PREV DISCUSSION... /issued 213 PM MDT Thu Aug 30 2018/
SHORT TERM...Tonight through Saturday
Showers and isolated thunderstorms expected to develop this
afternoon/evening in response to a shortwave moving out of Nevada.
Through much of the day we`ve already seen increased cloud cover
through the central mountains and even a few light echoes. Evening
activity should be largely confined to an area from Chilly to
just north of Island Park. Hi-res models are handling ongoing
activity fairly well, but earlier runs of the HRRR have proven a
little to bullish on intensity.
The added cloud cover should keep temperatures a little lower
over the central mountains, while the Arco Desert southward
should see temperatures get to or above yesterday`s readings
with broader insolation.
A cold front will cross the region tomorrow and should produce little
more than passing mid-level clouds. Depending on the timing of the
front and associated clouds, temperatures could be a little
tricky. Adjusted the central mountains down a few degrees, while
keeping the southern highlands close to guidance. Regardless, with
the front to our southeast Friday night, lows Saturday morning
will really drop off below seasonal averages.
Saturday will be a pleasant day with dry westerly flow re-
establishing, clearing skies and below average temperatures.
TAX
LONG TERM...Saturday Night through Thursday
The pattern will remain fairly quiet through the end of the
weekend under a brief spell of zonal flow aloft. Models still
having a difficult time determining when amplification of the
pattern takes place again. Previous runs of the deterministic
guidance showed a weak and dry trough moving into the region
Monday into Tuesday. 12z runs of the EC/GFS, however, bring a
deeper, wetter trough inland by Tuesday, in varying degrees. This
trend is further bolstered by at least broad consensus among
ensemble guidance. With this in mind, have introduced PoPs into
the forecast Tuesday and Wednesday, but with low confidence, kept
them under the blend output. Guidance diverges thereafter and a
blend was heavily utilized to round out the extended. TAX
AVIATION...Dry cold front pushing through today will bring some
wind gusts to the terminals this afternoon, tapering off in the
evening. VFR conditions will prevail with low probability of
thunderstorms approaching the terminals. Hinsberger
FIRE WEATHER...Concern today for winds and RH across the Snake
Plain as a dry cold front pushes through. The Arco Desert could see
winds gusting to 35 mph with humidity near 15 percent. Otherwise,
some isolated thunderstorms will be possible this evening. Cooler
temps and higher RH values tomorrow will mitigate any potential fire
concerns, and winds for the rest of the week should be lighter.
Another cold front will be pushing through next Tuesday with
vigorous upper level support. GFS is flip-flopping on availability
of moisture available to trigger thunderstorms, and the ECMWF is
running with a drier zonal pattern for the period. Model
inconsistencies are giving us a low confidence for the first half of
next week. Hinsberger
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$