Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/26/19
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
1003 PM EDT Thu Apr 25 2019
Showers and a few thunderstorms will be possible through
tonight as a low pressure system moves through the Ohio Valley.
A cold front will push east across the area on Friday with a
drier, cooler air mass moving into the region behind it. Another
low pressure system will bring additional rain chances to the
area later Saturday afternoon into Saturday night.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
With low pressure centered over Southeast Indiana, isolated
severe weather from rotating cells has developed this evening
in a weakly unstable but strongly sheared environment. We have
received a few reports of wind damage and hail, with more cells
to interrogate on the radar.
The NAM/ CMC and several of the 12Z higher res models are
suggesting some heavier rain swaths with some localized amounts
of 2 to 3 inches possible. The GFS and the ECMWF are not as
aggressive, with the ECMWF keeping the heaviest swath to our
northwest. FFG is on the higher side with 6 hour guidance
generally in the 2 to 2.5 inch range. Considered going with a
flood watch across parts of our northwest to account for this.
However, with some uncertainty between the models in the
location of the heaviest swaths and the latest RAP and HRRR
continuing to shift farther to the northwest, have opted to hold
off on a watch. That being said, think there is potential to see
a fair amount of flood advisory type issues tonight and will
continue to mention this threat in the HWO.
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
The mid/upper level trough axis will shift off to the east
through the day on Friday with the surface low shifting off to
our northeast and the cold front moving east of our area. This
will lead to a decreasing trend in pcpn from west to east as we
progress through the day. As drier air moves in, we will also
see at least some partial clearing work in from the west through
the afternoon. In developing low level CAA behind the front,
winds will be on the increase and become gusty. Have trended a
little closer to the more mixy GFS, with wind gusts in the 30 to
35 mph range possible. Highs on Friday will be in the upper 50s
to lower 60s.
Mainly clear skies are expected for Friday night with lows
ranging from the upper 30s in the north to the lower 40s in the
south. It does look like the gradient will help keep the winds
up enough through the night to limit any frost development
across the north Friday night.
.LONG TERM /SATURDAY THROUGH THURSDAY/...
An unsettled weather pattern will be in place for this weekend and
into next week with multiple systems moving through the region.
Although dry conditions will start out the day on Saturday an
approaching low pressure system will bring precipitation chances to
the region beginning during the afternoon hours on Saturday.
Precipitation will taper off Sunday morning. Instability is limited
during this time and therefore generally kept any thunder mention
out of this time period or at a minimum.
Clouds will decrease for Sunday evening into the first part of
Sunday night. There is the potential for some frost across central
Ohio if winds decrease for a long enough period of time. At time
point limited frost mention to central Ohio and kept it patchy.
The dry weather for Sunday night will be short lived as
precipitation chances move back into the region for Monday and
remain in place through the week. Warmer temperatures will be in
place during this time with highs generally in the 60s in 70s. A
few 80 degree temperatures will also be possible near and south of
the Ohio River on Wednesday and Thursday. There is at least some
instability each day and therefore have a thunder mention in the
forecast as well.
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Flight conditions will be affected by weather associated with
low pressure moving from Central Indiana to Northwest Ohio.
Showers and thunderstorms will be accompanied by IFR
visibilities, and wind gusts as high as 35 knots this evening at
CVG and LUK. Thunderstorms may decrease in strength overnight,
while showers increase in coverage, and MVFR ceilings become
As the low lifts north on Friday, winds from the northwest will
increase in speed with gusts over 30 knots. VFR should arrive
Friday afternoon as high pressure moves closer, while wind
speeds gradually subside by Friday evening.
OUTLOOK...MVFR conditions will be possible on Saturday night
into Sunday morning.
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
647 PM CDT Thu Apr 25 2019
.SHORT TERM... (Through Late Friday Afternoon)
Issued at 358 PM CDT Thu Apr 25 2019
Low pressure over the mid Mississippi Valley will be exiting the
region this evening, taking the persistent rain over southeast and
east central Missouri and southern Illinois with it. The rain
should begin moving a little more quickly over the next few hours as
the upper level low trough continues to open up and accelerate to
the east-northeast. Meanwhile, a secondary cold front which is
currently pushing through south central Iowa and northwest Missouri
will continue moving southeast tonight, and sweep through southern
Illinois and southeast Missouri by 08Z-10Z. A broken line of
showers is already forming just ahead of the front in southeast Iowa
and north central Missouri. Short range guidance including all of
the convection allowing models continue to develop convection ahead
of the front late this afternoon and push the broken line into
northeast and central Missouri and west central Illinois...and even
into east central Missouri and southwest Illinois by mid-evening.
RAP and GFS do show a bit of instability ahead of the front, so have
kept isolated thunder mention in the forecast with this convection.
Most guidance shows the line weakening between 03-05Z.
Cooler and drier air will filter into the mid Mississippi Valley
behind the front tonight with lows dropping into the 40s. There
will also likely be some gusty winds of 20-30 mph behind the front
tonight and Friday. While we`ll start Friday on the cool side, it
looks like a mostly sunny day, and even with northwest wind
temperatures should easily rebound into the mid 60s per
guidance...and these temperatures agree well with upstream highs
over Nebraska this afternoon. Lows may be tricky on Friday night
though as the wind drops off during the evening and then turns back
to the south ahead of the next system. With dry air in place and a
clear sky temperatures could drop fairly quickly in the evening and
then remain nearly steady in the pre-dawn hours of Saturday.
.LONG TERM... (Friday Night through Next Thursday)
Issued at 358 PM CDT Thu Apr 25 2019
An active pattern is staged to impact the Midwest through the
period. The greatest potential for heavier rain comes next week as a
boundary becomes nearly stationary and meanders through the Midwest.
This will also bring the potential for a north/south spread in
The first system will come in the form of a surface low passing
southeast through the Dakotas, under an upper level shortwave. As it
progresses east, it will continue to the place the MO/IL region
deeper into warm air advection and associated southwesterly flow.
Moisture will continue to increase, along with the presence of
isentropic lift over Missouri Saturday morning. Showers are expected
to develop over Missouri Saturday morning and toward the MO/IL
border around early afternoon. Activity will move into Illinois
through mid-afternoon. Showers are likely to be the mode of activity
with little/no MLCAPE and early morning clouds should keep
temperatures in the 60s/near 70 with little opportunity for diurnal
surface heating, despite warm air advection.
Behind the first round of showers will likely be somewhat of a lull
Saturday afternoon. Overall rain chances will remain limited with
hit-or-miss showers until the surface low`s trailing cold front
approaches from the northwest late Saturday afternoon into Saturday
evening. Even this isn`t all that impressive with scattered activity
confined to a narrow area of convergence along the front. Given
marginal convective potential, thunder was kept to slight wording in
the going forecast. All should move east with the front by late
Saturday evening. Clouds could break late with winds remaining
between 5-10 mph, even in the coldest areas of NE Missouri. therefore,
frost still looks like a long shot.
Sunday currently looks like a dry day between systems with a surface
high pushing through the Upper Midwest underneath upper level
ridging. There could be some lingering low level moisture through
the morning hours, but the loss in moisture depth from late morning
into the afternoon will allow for clearing. Temperatures will be
held in the 60s as cooler air continues to advect in behind the
aforementioned cold front.
Upper level flow goes nearly zonal late Sunday into Monday, taking
on the slightest tilt out of the southwest. Additional disturbances
will begin to push west to east through the zonal flow during this
period. As this occurs, the surface boundary stalls through the
region, becoming the focus for the storm track from early week
through the midweek period. I believe the main feature we will need
to watch will be the building ridge over the western Atlantic and
southeast CONUS. Should this ridge continue to build westward, it
lending to warmer and more moist southwesterly flow over the region.
The strength and westward build of this ridge will be a factor in
boundary placement, determining the track of additional waves along
the boundary, resulting rainfall totals and north/south temperature
spread in the Monday through Wednesday timeframe. For now, each of
the three days will involve chances for rain with the potential that
some rain could be heavy given ample moisture transport out of the
.AVIATION... (For the 00z TAFs through 00z Friday Evening)
Issued at 624 PM CDT Thu Apr 25 2019
Rain has moved southeast of the St. Louis area terminals and the
MVFR ceilings at KCPS will move out shortly. Otherwise, a line of
showers and isolated thunderstorms will move southeast evening
bringing a brief shower with low VFR or high MVFR ceilings and
visibilities at the terminals this evening. Winds will increase
from the northwest this evening with gusts above 20kts. Dry and
VFR conditions are expected after 06Z.
SPECIFICS FOR KSTL:
Rain has moved southeast of the terminal with VFR conditions
currently. A line of showers currently over northeast Missouri
will move southeast into the terminal around 03Z with brief low
VFR or high MVFR ceilings and visibilities. Then dry and VFR
conditions are expected the rest of the period.
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
900 PM CDT Thu Apr 25 2019
.DISCUSSION...See updated information for land areas below.
.UPDATE...Upper level trof axis was pivoting eastward over the
eastern MS/western AL state borders this evening. On the east
side of this feature, deep convection has moved rapidly eastward
with the back edge of the shield of showers and embedded storms
moving out of the far eastern zones. To the south, beyond 20
nautical miles offshore, organized stronger storms continue to
track eastward and has required the issuance of marine warnings.
Storms may remain potent for awhile longer well offshore. A large
plume of deep dry air, per water vapor satellite imagery, was
advancing over the forecast area in the wake of earlier passing
storms. Despite this, forecasters note bands of showers rotating
eastward over central/northern MS within the colder portions of
the upper trof axis itself where the back edge of -12 to -14C 500
mb air is aiding in some instability aloft. Lingering moisture was
also being lifted by an eastward moving north to south draped
frontal boundary positioned from western KY to the central Gulf.
Following the departure of the bulk of precipitation, the 26.00Z
HRRR high resolution guidance supports the passage of isolated to
perhaps scattered showers/thunder thru the remainder of the
evening. This activity is shown mainly over the interior with an
eastward shift into the eastern zones overnight, as the upper
level trof axis and surface front makes passage. /10
.PREV DISCUSSION... /issued 743 PM CDT Thu Apr 25 2019/
DISCUSSION...See updated information for land areas below.
UPDATE...Shield of showers and embedded storms have moved
steadily eastward early this evening and is now over the far eastern
zones. Strongest convection is confined to the 20 to 60 nautical mile
zones over the marine area and will remain so thru mid, to perhaps
late evening. Over the land zones, the severe weather threat has
ended. Convective watches have been cancelled and headlines removed
from public zones. Another cluster of showers and isolated storms
were developing over eastern MS and has been moving east. West of the
higher PoPs this evening in the eastern zones, will maintain a small
PoP to account for new activity to the northeast. /10
PREV DISCUSSION... /issued 649 PM CDT Thu Apr 25 2019/
DISCUSSION...Updated for latest aviation discussion below.
26/00Z Issuance...Rain shield is moving east across the area, now
primarily east of a Camden to Gulf Shores line. The stronger
storms are now located out over the Gulf to the south. Rains will
be ending across nearly the entire area by around 20/03z. Low
clouds (MVFR) will persist through most of the night, with some
patchy light fog possible (but generally MVFR or greater). Light
east to southeast winds overnight, becoming more southwesterly
early Friday morning and then light to moderate northwesterly
late Friday morning. 12/DS
PREV DISCUSSION... /issued 532 PM CDT Thu Apr 25 2019/
DISCUSSION...Updated for latest marine discussion below.
MARINE...Currently have a well defined book-end vortex currently
moving east across the Gulf just offshore of the Alabama coast
south of the mouth of Mobile Bay. KMOB velocity data is indicating
winds up to as high as 74 knots just below 3000 feet. Special
Marine Warnings are in effect for much of our marine area, where
localized wind gusts above 50 knots and very rough seas are
PREV DISCUSSION... /issued 358 PM CDT Thu Apr 25 2019/
NEAR TERM /Now Through Friday/...As of 315 PM this afternoon, a
convective outflow boundary extends from Butler county southwest
generally along I-65 down to Mobile county. A weakly defined warm
front appears to extend inland across the western FL panhandle and
intersects the outflow boundary somewhere in the vicinity of Conecuh
county (where remnants of earlier strong convection has flared up
once again). At this time most of that inland convection is expected
to continue over our eastern interior zones into early evening,
generally remaining strong but sub-severe (although an isolated
severe storm could be possible). Further south toward the coast in
the areas bounded by by old outflow boundary to the west and the
warm front to the east (generally Mobile, Baldwin, Escambia FL,
Santa Rosa and Okaloosa counties) we still have a severe threat this
evening, and a Tornado Watch continues until 8 PM CDT. Cooling cloud
tops associated with intensifying convection over the offshore MS
coastal waters that HiRes models indicate will move east-northeast
across our coastal counties early this evening and generally moving
east of our area by late evening. This stronger convection will be
coincident with the strong 30 to 40 knot low level jet and the
better instabilities with MLCAPES continuing to approach 1500 J/KG
in this area. Some severe storms with damaging wind gusts and/or a
brief tornado possible. Could see some lingering showers over the
eastern half of our forecast area overnight into the predawn hours
Friday, but all precipitation is expected to have moved east of our
area after daybreak on Friday with no rain expected for the
remainder of the day. Lows tonight in the upper 50s over
northwestern counties to lower 60s elsewhere. Highs on Friday will
be ranging from the mid/upper 70s to the lower 80s. 12/DS
SHORT TERM /Friday night Through Sunday night/...Weak upper
ridging builds into the eastern CONUS in the wake of today`s
shortwave trough, bringing quieter weather and clearer skies to
the local area this weekend. A weak impulse passes by to our
north on Sunday and brings another front south into central and
northern AL/MS, where it should stall well north of the local
area. No precip is expected in our area with this front due to a
lack of moisture and forcing, though areas well inland may see
some additional cloudiness on Sunday. Plenty of daytime heating
beneath mostly clear skies will support high temps in the upper
70s and low 80s both Saturday and Sunday. Dry air and efficient
radiative cooling help overnight lows dip into the upper 40s
inland and low 50s along the coast Friday night, then low to mid
50s everywhere Saturday and Sunday nights. /49
LONG TERM /Monday Through Thursday/...Upper ridging amplifies
over the eastern CONUS as we head into early next week, leading to
stronger subsidence and a continuation of warm and sunny weather
for the local area. No rain chances in the forecast until late
next week. High temps reach the low to mid 80s along the coast and
mid to upper 80s inland each afternoon through the long term. High
surface pressure over the eastern Gulf maintains a light southerly
wind through the period, which helps gradually bring Gulf moisture
back into the area. As a result, overnight lows see a slow warming
trend, ranging from upper 50s Monday night to mid 60s by the end
of the week. /49
MARINE...A moderate to strong onshore flow will continue across the
marine area tonight, gradually subsiding after midnight. A Small
Craft Advisory continues for the Gulf Waters, MS sound and southern
Mobile Bay until 1 AM, with SCEC elsewhere. Some strong to severe
storms will be possible near shore early this evening, but
convection is expected to move on off to the east of our marine area
late this evening. Winds will shift to the northwest and decrease
somewhat behind the line of storms as a cold front moves east across
the coastal waters. A light to moderate offshore flow is then
expected to continue Friday through Saturday, before becoming more
east and southeasterly Sunday trough the early part of next week as
surface high pressure builds east across the marine area. 12/DS
AL...High Rip Current Risk through Friday morning for ALZ265-266.
FL...High Rip Current Risk through Friday morning for FLZ202-204-206.
GM...Small Craft Advisory until 1 AM CDT Friday for GMZ631-632-650-
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Area Forecast Discussion
National Weather Service Marquette MI
736 PM EDT Thu Apr 25 2019
.SHORT TERM...(This evening through Friday)
Issued at 428 PM EDT THU APR 25 2019
Water vapor imagery and RAP analysis show a vigorous shortwave
dropping se over southern Manitoba. This will be the next feature of
interest for Upper MI. Closer to home, healthy upper divergence from
the right entrance of 110kt upper jet extending from northern Lake
Superior to southern Quebec has lead to considerable high cloudiness
across the fcst area today. It has also supported an expansion of
shra to the ne into far s central Upper MI, mainly Menominee County.
Separate from this area of shra, more shra have recently developed
around KIMT due to weak instability underneath the larger scale
Shra will persist for the next several hrs over s central Upper MI.
Not expecting the shra to expand n of where they are currently
occurring as the upper diffluence is beginning to shift e. In
addition, radar imagery shows an overall s and e trend to the pcpn.
Attention then turns to the vigorous shortwave to the nw. This wave
will move across Upper MI Fri morning. Associated cold front will
swing across the fcst area overnight and will have exited by 12z
Fri. With track of the shortwave across Upper MI, best forcing will
pass by just to the n and e. Still, there could be a few -shra along
the front. If so, only the nw and possibly the n central/ne fcst
area would be affected by a brief, isold -shra. Area of low-level
moisture following the front will combine with daytime heating and
incoming 850mb thermal trof to produce considerable stratocu for a
time on Fri. These clouds should be rather short-lived over the w as
much drier air arrives in the aftn. Farther e, may end up turning
mainly cloudy late morning thru the aftn. Some of the models are
generating some light pcpn in the upslope areas of the w. Seems
overdone given the shallow moisture depth. Could be some -dz if
there is enough low-level moisture for a low stratus deck, but not
seeing much in the way of postfrontal low-clouds upstream currently.
Have thus left out any pcpn mention for now. Bigger impact of this
shortwave will be the wind. Rather vigorous caa occurs, especially
across the central and eastern fcst area during the day Fri to
increase mixing. Higher sun angle/stronger insolation at this time
of year will also aid the mixing. Fcst soundings show the potential
to mix into 35 to as high as 45kt winds within a few thousand feet
of the ground with the strongest winds aloft to tap into across the
eastern fcst area. While not particularly strong, there will be a
favorable orienation of the incoming pres rises for an additional
isallobaric wind component to the nw/nnw winds, especially e. As a
result, expect wind gusts to 40-45mph across roughly the e half of
the fcst area Fri aftn. Later shifts will need to consider a wind
advy if it appears gusts will be frequently aoa 45mph. To the w,
gusts will be mostly in the 25-35mph range. With the blustery
winds/caa and clouds, it will be a chilly day. Temps over the e will
likely fall into the 30s during the aftn. Temps may reach the upper
40s/around 50F toward the MI/WI stateline late in the aftn.
.LONG TERM...(Friday night through Thursday)
Issued at 432 PM EDT THU APR 25 2019
Models suggest that a progressive pattern will prevail through the
CONUS as a mid level trough over north central Canada slowly drifts
southwest into western Canada. Shortwaves moving through the
northern Great Lakes will bring pcpn chances to Upper Michigan
Monday and again from late Wed into Thu. Temperatures are expected
to remain at or below normal through the period.
Friday night into Saturday, a sfc ridge will build into the region
bringing diminishing winds Friday along with clearing. Pcpn with the
shrtwv and sfc low moving through IA into IL will remain south of
Upper Michigan. Stronger winds and mixing over the east will keep
temps in the upper 20s while readigns drop to the lower 20s inland
west. Sunshine and mixing in a very dry airmass will likely drop
dewpoints below guidance into the single digits resulting in low RH
values despite the cold air.
Sunday, Mid level and sfc ridging will continue to dominate the
region with dry weather and gradual warming as highs rebound into
the mid and upper 40s north to the lower 50s south.
Monday, Models have trended toward a stronger shrtwv and sfc
trough with higher POPs mentioned. Overall QPF is likely to remain
light given limited moisture inflow, with overall amounts in the
0.10-0.25 inch range.
Tue-Thu, there is lower confidence with the timing/strength of the
shrtwv and sfc trough lifting northeast from the plains from Wed
into Thu. Expect greater moisture advection toward the northern
Great Lakes with PWAT values to near an inch with the potential for
moderate rainfall amounts.
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 735 PM EDT THU APR 25 2019
With low-levels remaining relatively dry, VFR conditions will
prevail at KIWD/KMCX/KSAW thru tonight. A cold front moving across
the area tonight will be followed by blustery nw winds on Fri,
especially at KCMX/KSAW where gusts to 30kt or higher are expected.
In addition, colder air and low-level moisture will likely result in
MVFR cigs developing during the morning/early aftn. Skies will clear
by Friday evening with diminishing winds.
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 428 PM EDT THU APR 25 2019
Ahead of an approaching cold front, winds across Lake Superior will
be on the lighter side, under 20kt. The cold front will pass across
Lake Superior late evening thru the overnight, bringing a wind shift
to the nw. Winds will then ramp up on Fri with gales developing over
the central and eastern part of Lake Superior. Will probably see a
few hrs with gusts as high as 45kt. After a period of winds gusting
20-25kt over the w in the morning, winds will fall back to mostly
under 20kt in the aftn. Winds will diminish blo gale force over the
eastern part of Lake Superior during Fri night. Winds will fall back
under 20kt over the weekend as high pres builds into the northern
Gale Warning from 2 PM Friday to 4 AM EDT Saturday for LSZ251-
Gale Warning from 11 AM Friday to 2 AM EDT Saturday for LSZ250-
Gale Warning from 11 AM to 8 PM EDT Friday for LSZ248-249-265.
Gale Warning from 9 AM to 5 PM EDT Friday for LSZ244-245-264.
Gale Warning from 2 PM Friday to midnight EDT Friday night for
Area Forecast Discussion
National Weather Service Morristown TN
931 PM EDT Thu Apr 25 2019
.DISCUSSION...Forecast generally on track this evening with a few
minor updates. Biggest change was to refine hourly POPs to match
up with latest radar trends and HRRR runs. Still looks like a few
isolated storms could be possible later tonight but mainly
expecting rain showers as current MLCAPE values are pretty low
across the area, in the 200 to 300 J/kg range. Also made tweaks
to hourly temps and dewpoints. All other elements on track. Will
issue new zones.
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 59 71 48 79 / 80 30 10 10
Knoxville McGhee Tyson Airport, TN 59 68 45 77 / 80 70 10 10
Oak Ridge, TN 59 69 45 78 / 80 50 10 10
Tri Cities Airport, TN 58 63 41 73 / 80 80 20 10
TN...Wind Advisory from 11 AM to 8 PM EDT Friday for Blount Smoky
Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
Mountains-Southeast Carter-Southeast Greene-Southeast