Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/24/17
Area Forecast Discussion
National Weather Service Bismarck ND
955 PM CDT Thu Mar 23 2017
.UPDATE...
Issued at 952 PM CDT Thu Mar 23 2017
Will update sky cover and POPs as the precipitation area moves
east and shrinks. Otherwise current forecast looks ok with fog
forecast to become more widespread later tonight.
UPDATE Issued at 725 PM CDT Thu Mar 23 2017
Band of steady rain now over Bismark and Mandan so updated to
likely pops for the early evening.
UPDATE Issued at 535 PM CDT Thu Mar 23 2017
Used the regional radars and the HRRR simulated DBz to refine the
POP chances this evening. This band of rain will translate
southeast slowly and diminish in areal extent and intensity with
time. Ended the thunderstorm threat as the low level lapse rates
have significantly diminished and the instability greatly
diminished as well.
&&
.SHORT TERM...(This evening through Friday)
Issued at 242 PM CDT Thu Mar 23 2017
Precipitation this afternoon and evening with isolated
thunderstorms possible south central this afternoon highlight the
short term forecast.
Isolated convection as of 1945 UTC has developed in an area of
clearing and destabilization across far south central North
Dakota, especially along zones of differential heating on the
cloud edges. Thus, added a mention of thunderstorms for these
areas for this afternoon and early evening.
Otherwise, rain across the southwest through the upper James River
Valley in association with strong 700-600mb frontogenesis will
slowly diminish through the early evening. The 15-18 UTC high
resolution, rapidly updating suites within their visibility
forecasts do suggest the potential for fog develop tonight into
Friday morning which is plausible given the abundant low level
moisture in place across the area.
.LONG TERM...(Friday night through Thursday)
Issued at 242 PM CDT Thu Mar 23 2017
Above normal temperatures highlight the extended forecast.
The 12 UTC global models are in agreement on split flow across the
Northern Plains Friday and Saturday with an upper level ridge
potentially building across the region Monday into Tuesday, before
another potential return to split flow late next week. This
overall favors above normal temperatures with highs in the 40s and
50s and sporadic, weak precipitation events.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 632 PM CDT Thu Mar 23 2017
A southwest through northeast band of rain remains across
southwest and central North Dakota at 6 PM CDT. This will
translate very slowly southeast as it diminishes and ends after
around midnight.
The CONSshort guidance depicts widespread fog after midnight
particularly in KMOT, but patchy fog elsewhere as well. KMOT has
VLIFR develop in fog 08z through 12z gradually improving to IFR
after 16z and VFR after 19z. IFR Conditions in BR at KBIS between
11-17z. Otherwise VFR to MVFR late tonight KISN and KJMS and VFR
at KDIK.
&&
.HYDROLOGY...
Issued at 242 PM CDT Thu Mar 23 2017
Lake Darling will increase discharge to 1200 cubic feet per second
Thursday afternoon. Increased discharge will result in river levels
rising above minor flood stage later today. Additional increases are
likely over the coming days. Stay tuned to the Bismarck Office of the
National Weather Service for updates on future forecasts.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...WAA
HYDROLOGY...AYD
Area Forecast Discussion
National Weather Service State College PA
1119 PM EDT Thu Mar 23 2017
.SYNOPSIS...
As an upper level ridge builds over the eastern US we could see
brief period of freezing rain Friday morning than a rapid warm
up. Our mid-tropospheric heights and temperatures will be
slightly above normal into next week. A few week systems could
bring showers to the region but at this time the pattern does
not suggest any significant rain events.
&&
.NEAR TERM /UNTIL 8 AM FRIDAY MORNING/...
Under clear skies temperatures have faded away rapidly. Many
locations have fallen into the 20s. Difficult to display this
consistently and collaboratively in our grids.
Satellite imagery shows a larger area of deep cold cloud tops
over Michigan and leading cirrus over Ohio. Clouds are coming
and behind them some rainfall is coming.
Due to the cold air in the boundary layer the rain will likely
start as freezing rain over northern and some central areas.
Farther south less QPF is forecast and later in time so less
likely they will see freezing rain.
The HRRR and its coarser twin the RAP show the precipitation
coming in slower with each run. Likely most areas will not see
any precipitation much before 4 to 6 AM. In with 0.01 to about
0.10 inches of QPF a light glaze is possible before 8 AM in
northern and central areas.
Most of the region in the advisory for freezing rain could see a
light glaze this morning. If and where it rains.
&&
.SHORT TERM /8 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
There will be a lingering threat for isolated freezing rain in
the 8 AM to 10 AM timeframe in some locations and perhaps 11 AM
in colder areas of our northeastern areas. But the forecast
rapid warm up and the March sun angles should help reduce this
fast. One might not see the sun but the shortwave energy will
reach roads and walks.
The chance of rain diminishes during the day.
There should be a very rapid warm up by late morning and into the
afternoon. Winter will have exited stage East and it may be
along time before we see any significantly cold weather again.
High temperatures should range mainly from the 50 to the lower
60s. Warmest in the south/southwest.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
At the outset of the longer term period the models are in fair
agreement in timing and strength. All are indicating a boundary
just to the north of Pennsylvania with a large upper level low
moving through the central midwest. A negatively tilted ridge
over the mid Atlantic will allow for stable but cloudy weather
into Saturday. Lows Friday night into Saturday should range from
the upper 40s to low 50s. There could be light rain showers on
Saturday but warm and stable. A cooler moist boundary should
move into the region Sunday out ahead of the approaching low.
Have adjusted POPs for timing and intensity. QPF remains
variable but possible wet period Sunday into Monday.
Above average temperatures are expected over the weekend with
the warmest day likely on Saturday with some sites approaching
70F over southern PA. Sunday should be markedly cooler behind
a backdoor cold front and a likelihood of rain. However, above
average temperatures (especially nighttime) appear very likely
through early next week, as 12Z GEFS indicates Pa remains
beneath a mean upper level ridge and plume of anomalous PWATs.
The chance of showers will spike with passage of next shortwave
Tuesday into Wednesday.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Mid level cloud is on the increase along with surface winds
veering to 90-140 degrees. Light precip will move across the
region between 06-18z Friday, starting as RA/FZRA/PL before
transitioning to all RA by 15z Friday. Added PROB30 group to
hedge toward brief period of ice mix around daybreak Friday.
Conditions will remain generally MVFR even through the precip
times. Possibly a brief period of IFR in KBFD and KJST from
10-14Z.
Precip ends by 18z in all locations with increasing ceilings.
Outlook...
Sat...Mainly VFR. Chance of rain northern 1/2 airspace.
Sun-Tue...Sub-VFR with periods of rain.
&&
.CLIMATE...
Minimum temperature records for 3/23 at select sites:
MDT: 14 in 1934
IPT: 8 in 1906
BFD: 5 in 1959
AOO: 15 in 1960
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 4 AM to 11 AM EDT Friday for
PAZ005-006-010>012-017>019-026>028-037-041-042-045-046-049>053-
056>059.
&&
$$
SYNOPSIS...Grumm
NEAR TERM...Grumm
SHORT TERM...Grumm
LONG TERM...Fitzgerald/Ceru
AVIATION...DeVoir/Evanego/Tyburski
CLIMATE...
Area Forecast Discussion
National Weather Service Cheyenne WY
932 PM MDT Thu Mar 23 2017
.UPDATE...
Issued at 926 PM MDT Thu Mar 23 2017
Sending one last update for this evening. Precipitation has been
limited in coverage, with most of it still across western Nebraska
in the form of rain. Little if any snow has been observed further
west with light rain just beginning in Cheyenne in the last 20
minutes. Analysis of the current observations and satellite loop
shows the storm system potentially developing even further south
than previously expected. Will keep our winter headlines along I80
from Arlington to cheyenne going for now, but would not be
surprised if some of these are cancelled early. For the rest of
the evening, lowered POP further west across Carbon county with
only some low clouds being reported. Lowered accumulations a bit
as well. Also becoming less concerned with snowfall across the
southern panhandle with the new 00z models showing too much warm
air over this area and snow levels quite a bit higher.
&&
.SHORT TERM...(This evening through Friday)
Issued at 318 PM MDT Thu Mar 23 2017
A very active 18 hours ahead for the region as a strong storm system
spins across the Rockies bringing snow to parts of the area along
with gusty northerly winds, and cooler temperatures. Afternoon
satellite pix depict this system spinning across Utah currently with
KCYS 88D returning showers along with a few wk thunderstorms along
the Pine Ridge in the N panhandle west back towards Rawlins. 20Z SPC
mesoanalysis does show a few pockets of 500-1000 j/kg pooling across
parts of the area, but agree with the latest few SPC outlooks that
point to just mainly general thunderstorms across the region. At the
surface...pressures have been steadily falling all day in along the
front range with a well defined dryline located between Pine Bluffs
and Kimball with 20z Td`s of 12F and 40F, respectively.
Cold front was knocking on the doorstep of the northern zones
this afternoon and will drop south across the CWA through 9 PM.
Recent HRRR output, suggest area of shower and embedded
thunderstorm activity will expand across the eastern plains
through the rest of the evening along and ahead of this cold
front. Snow-levels will fall this evening turning rain to snow,
first over the I-80 summit and eventually into adjacent higher
elevations (above 5000 feet) by around midnight. At the same time,
with the cyclone deepening to the south, north winds will
increase with gusts of 30-45 mph for a time across the eastern
plains. The combination of these strong winds and 3-7 inches of
new snow has prompted the issuance of a Winter Storm Warning
across the southern Laramie Range. Areas from Arlington to Laramie
and in the vicinity of Cheyenne will be well positioned for 2-3
inches of snow late tonight and for the Friday morning commute.
Again the combination of strong winds and these accumulations has
led to the issuance of a Winter Weather Advisory for these areas.
Some question as to just how far east along I-80 snow will be able
to fall especially given just how dynamic this system is, but for
now have kept accumulations Kimball to Sidney to an inch or less
and don`t suspect to see significant impacts there. Evening shifts
will need to watch for the potential of a 3-6 hours of high wind
potential for Kimball-Sidney from 09-15z. The system departs as
quickly as it moves through, allowing for drying conditions by mid
morning Friday and clearing skies through the afternoon. High
temperatures on Friday only to reach the 40s above 5500 feet, with
5 0s for lower elevations. Winds will gradually subside thru
Friday afternoon.
.LONG TERM...(Friday night through Thursday)
Issued at 318 PM MDT Thu Mar 23 2017
As the main upper low moves to our southeast, precipitation will
taper off around Sidney by 6 PM Friday with upper ridging keeping
a short dry pattern in place for Friday night. The weekend leads
off a rather active period of passing upper systems bringing
chances of snow in the higher elevations and mostly rain or a mix
below 6000 ft across the eastern zones. Given that the position
of the passing shortwaves Saturday into Sunday, then again Tuesday
into Wednesday, we don`t tap any deep cold air. Overall impacts
from winter weather this next week doesn`t look overly impressive
with any of these systems. The only thing to pay attention to
initially will be potential for localized higher amounts of new snow
to near 6 inches in the higher elevations of the Snowy Range this
weekend, but that is about it for anything that would approach
significant snowfall accumulations.
&&
.AVIATION...(For the 00Z TAFS through Friday afternoon)
Issued at 550 PM MDT Thu Mar 23 2017
Scattered showers with isolated thunderstorms will continue across
parts of SE Wyoming and western Nebraska early this evening. Cold
front currently along a line from around KAIA to KCYS across the
high plains, and then extending northwest, north of KLAR toward KRWL
west of I-25. Behind the cold front we will see a cold rain
switching to snow overnight in Wyoming. We expect lowering
ceilings/visibilities across the entire area, but more impactful
down to LIFR for Cheyenne and Laramie late tonight.
&&
.FIRE WEATHER...
Issued at 505 PM MDT Thu Mar 23 2017
Conditions are improving this evening as a cold front rapidly moves
southward across the high plains, ending the fire weather threat.
Fire weather concerns will be low for Friday with widespread rain or
snow expected late tonight and early Friday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 9 AM MDT Friday for WYZ110-115.
Winter Storm Warning until 9 AM MDT Friday for WYZ116-117.
Winter Weather Advisory until 9 AM MDT Friday for WYZ118.
NE...None.
&&
$$
UPDATE...TJT
SHORT TERM...CAH
LONG TERM...JG
AVIATION...TJT
FIRE WEATHER...TJT
Area Forecast Discussion
National Weather Service Quad Cities IA IL
643 PM CDT Thu Mar 23 2017
...00z AVIATION UPDATE...
.SYNOPSIS...
Issued at 325 PM CDT Thu Mar 23 2017
18Z surface data has a warm front from eastern Nebraska into far
western Kentucky. Dew points were in the teens and 20s across the
Great Lakes with 30s from the northern Plains into the lower Ohio
Valley. Dew points of 40 and higher ran from the central Plains to
the Gulf Coast of Texas.
&&
.SHORT TERM...(This Evening through Friday)
ISSUED AT 325 PM CDT Thu Mar 23 2017
The 12z sounding tells the story. A large layer of dry air near the
surface which has keep most of the area dry. This dry layer has
moistened during the day allowing scattered showers and sprinkles to
develop. The forcing that developed the rain will continue moving
east northeast through sunset with the best chances of light rain in
the I-80 corridor up to highway 30 east of the Mississippi.
Two areas of forcing are moving across Iowa that have generated some
showers and thunderstorms. However, as this forcing moves further
away from the better moisture, the convection is slowly decaying.
RAP trends show an area of weak forcing developing in eastern Iowa
this evening and moving east northeast. This forcing may be just
enough to generate isolated showers or sprinkles during the evening
hours.
Late this evening and overnight mainly dry conditions are expected
as the front moves north of the area and the better forcing is
focused across the upper Midwest.
Temperatures will drop very little this evening before rising the
remainder of the night.
On Friday, mainly dry conditions are expected during the morning as
the better moisture and forcing remain west of the area. A possible
exception may be Buchanan, and parts of Delaware/Benton counties
that may see some light rain.
Friday afternoon moisture surges into the area as the storm system
approaches. Diurnal heating will allow showers and then
thunderstorms to develop from west to east during the afternoon
hours. The best chances for rain will be west of the Mississippi.
Temperatures should average well above normal.
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 325 PM CDT Thu Mar 23 2017
Forecast focus on a very active storm pattern with the potential for
four separate storm systems impacting the Midwest over the next 10
days. The storm track will extend from the Pacific Northwest to the
mid MS Valley bringing moderate to heavy rainfall amounts to the cwa.
Friday night and Saturday: Strong storm system to lift out of the
southern Rockies and into MO. Strong forcing, combined with a nice
warm conveyor belt out of the Gulf, will bring widespread rain and a
few embedded thunderstorms to the cwa. PWAT`s increase to over an
inch with a back-door cold front feeding in from strong high
pressure north of the Great Lakes. This warm moist feed aloft over
the "lake-enhanced" cold dome should bring widespread rain amounts
of at least an inch, possibly 2 inches at some spots in steadier and
heavier rainfall. With minimal instability over the cwa, the threat
of strong/severe storms looks to be well to our south.
Will go with the cooler MET guidance vs the MAV, with the superblend
basically taking a "middle of the road" approach. However, being
that the ECMWF does better at depicting back-door cold fronts this
model has even colder temperatures, but haven`t gone quite that cold
yet, for later shifts to consider. As of now, the grids will have
lows Friday night in the lower 40s far north to the lower 50s far
south. Highs on Saturday should range from the mid 40s nw to around
60 se. However, these readings could be 3 to 6 degrees too warm.
Saturday night and Sunday: The occluding/filling system will
gradually move to southern Lower MI with any lingering showers
coming to an end. Highs will be in the 50s.
Sunday night through Monday night: The next potent wave currently
slamming into the Pacific Northwest will quickly dive into the
central Plains and into MO early next week. This should bring
another widespread rain event to the cwa.
Later next week into the following weekend: Models suggest a couple
more strong storm systems taking a similar track. Both of these
systems may also bring widespread rainfall for late March/Early
April.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 631 PM CDT Thu Mar 23 2017
A warm front will lift north through the terminals tonight, and
there is a low chance of a shower at CID and DBQ ahead of the
front. Otherwise, generally vfr conditions expected with S/SE
winds around 10 kt and gusty at times. Have maintained low level
wind shear at all terminals by mid evening into early Friday
morning as winds increase to 40-50 kts in 1500-2000 ft agl layer.
Anticipate showers and storms to be on the increase across the
area mid to late Friday afternoon and especially Friday evening
ahead of an approaching cold front. Being late in the taf cycle
I have not made any mention, but will certainly be addressing for
06z tafs.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...Haase
AVIATION...McClure
Area Forecast Discussion
National Weather Service Goodland KS
649 PM MDT Thu Mar 23 2017
.UPDATE...
Issued at 644 PM MDT Thu Mar 23 2017
A Blowing Dust Advisory has been issued for the next few hours for
the counties south of I-70 and along and west of Hwy 27; in
Colorado and Kansas. There was a dust plum observed via
satellite. Dust was verified from a spotter and the Burlington, CO
ASOS site.
&&
.SHORT TERM...(This afternoon through Friday)
Issued at 339 PM MDT Thu Mar 23 2017
Early afternoon WV imagery and RAP analysis shows a trough becoming
negatively tilted near the Four Corners Region. SW diffluent flow
extends across the plains ahead of this upper trough. At the surface
lee trough is deepening with a trough axis near our northern CWA
and a dry line and possible warm front just south of our CWA.
This afternoon-evening: Mesoanalysis shows weakening CIN and axis of
2500 J/KG SB CAPE east of CO state line. Axis of 50-75 kt effective
bulk shear extends along the CO border. As cap is weakening we are
beginning to see CU field developing along and east of surface low
pressure. Short range guidance (RAP/HRRR) are showing thunderstorm
initiation along CO border within the hour, and increasing
coverage/possible mergers through the early evening. Shear profiles
at least within the effective layer are linear in nature, however as
LLJ increases around 00Z we may see low level veering (particularly
along warm front/trough axis) which could allow super cell
development. Greater concern will be for large hail and damaging
winds (particularly damaging winds due to high storm bases and
dry air masses). DCAPE values are already in the 1000-1500 J/KG
range. Due to the very high shear environment and possibility for
dry air entrainment/precip loading (based on moisture profiles)
raises the possibility for isolated gusts in excess of 80 mph.
Late tonight-Friday: Upper low closes off and deepens and is showing
by guidances to track near southern Kansas border (there are
variances). As has been the case guidance shows best precip coverage
across our NW CWA where occlusion/deformation zone sets up and
moderate to heavy rainfall will be possible. Wet bulb profiles on
GFS/ECMWF are borderline on rain/snow mix, however in our far west
we should see a change over in the 09-15Z time frame and a mix can`t
be ruled out in counties adjacent to CO border. I couldn`t rule out
moderate snow accumulations in our far west, however ground
temperatures are very warm and I am unsure how persistent the
snowfall would be. NAM is a cold outlier, but it should be noted it
shows the possibility for predominately snow spreading into NW
Kansas/SW Nebraska (similar conditions to eastern CO). GFS and ECMWF
do show temperature profiles cooling over NW KS during the day as
upper low transitions east, but this is separated from main precip
axis in the west.
It is worth noting that unless we see showers/isolated thunderstorms
fill in near upper low center, our southeast CWA may not receive any
precipitation Friday due to a dry slot moving from the southeast to
northwest. I trended PoPs down for those locations.
Regarding Wind/Winter Weather Highlights: Mixed layer winds should
support at least 60 mph along and west of the CO state line late
tonight and Friday (west to east progression in winds increasing). I
have less confidence in winds furthest east towards Hwy 83 and SW
Nebraska due to position on main wind max. I went ahead and upgraded
watch to High Wind Warning, but could see the counties east and
north remaining just below criteria. Where snow occurs (more likely
west) these winds should combine to crease blowing snow/near
blizzard conditions. Confidence was lower in the east due to better
consistency with GFS/ECWMF. I was also unsure of duration of
possible white out conditions, so decision was made to issue Winter
Weather Advisory for our eastern Colorado counties. We will need to
monitor trends, and make adjustments as necessary.
.LONG TERM...(Friday night through Thursday)
Issued at 1241 PM MDT Thu Mar 23 2017
Several wx systems set to affect the Tri State region for the
extended period. The first will occur Friday night as wrap-around
moisture from exiting system will mainly affect northern zones thru
06z Saturday. Second system will be a quick moving shortwave for the
latter portion of the upcoming weekend into Sunday night. A large
cutoff H5 low then swings into the southwest portions of the country
by Tuesday shifting eastward into the Southern Plains into Thursday.
High pressure set to affect the region in between affecting systems.
For Friday night...CAA accompanying the wrap-around moisture will
keep a rw/sw mix or all -sw for NE Colorado as temps slide into
the 30s. Areas east of the Colorado border will see light rain as
temps do not drop to see any changeover before precip exits. For
the end of the weekend system...temps will remain in a range to
keep all areas as light rain showers. QPF expectations will reach
possibly in a range of 0.10-0.20" for these two systems combined.
The prolonged nature of the upcoming mid week system for next
Tuesday into Thursday will bring in ample Gulf moisture for a 0.75-
1.00" potential QPF range with some localized higher amounts...
especially west of Highway 83. Colder air wrapping into area Wed
night into Thursday will bring best chances for snow showers to mix
with expected rain. Light accumulation possible for western zones.
For temps...near to above normal highs expected with a range from
the mid 50s to the mid 60s...warmest timeframes on Saturday and next
Monday which do coincide with surface ridging arriving before
shortwaves. Overnight lows will drop into the 30s for most nights.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 555 PM MDT Thu Mar 23 2017
KGLD and KMCK will have multiple aviation impacts during the TAF
period. During the remainder of the afternoon into to the evening
hours, both terminals will have the potential for thunderstorms.
Both terminals could see gusty winds through the evening hours.
KMCK is expected to see is LLWS during the evening hours of 02z
to 05z from the south around 40 to 45 kts.
Widespread rain chances are expected to develop into the overnight
hours and continuing through the remainder of the TAF period.
KGLD could see a rain/snow mix Friday morning into the afternoon
hours. With this rain and rain/snow chances over both terminals,
strong winds are expected. Gusty north winds will engulf both
locations at around 40 to 50 kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...High Wind Warning from 6 AM MDT /7 AM CDT/ to 6 PM MDT /7 PM
CDT/ Friday for KSZ001-002-013-014-027-028-041-042.
Red Flag Warning until 7 PM MDT /8 PM CDT/ this evening for
KSZ001-013-027-041.
Blowing Dust Advisory until 8 PM MDT this evening for KSZ013-027-
041.
CO...Red Flag Warning until 7 PM MDT this evening for COZ252>254.
Blowing Dust Advisory until 8 PM MDT this evening for COZ091-092.
High Wind Warning from 3 AM to 6 PM MDT Friday for COZ090>092.
Winter Weather Advisory from 3 AM to noon MDT Friday for
COZ090>092.
NE...Red Flag Warning until 7 PM MDT this evening for NEZ079.
&&
$$
UPDATE...CLT
SHORT TERM...DR
LONG TERM...JN
AVIATION...CLT
Area Forecast Discussion
National Weather Service Omaha/Valley NE
656 PM CDT Thu Mar 23 2017
.SHORT TERM...(tonight through Sunday)
Issued at 320 PM CDT Thu Mar 23 2017
Forecast concerns in the short term will be shower and
thunderstorms through Saturday with the slow moving storm system.
Where the best potential for severe weather is and what kind of
rainfall amounts may occur.
The KTOP/KOAX 12Z soundings from this morning showed moist
conditions through h7 with around 1 inch of pwat and steep 3-6km
lapse rates around 8 deg C/km. H9 winds increased to around 45kts
during the morning and a pocket of strong 0-3km bulk shear across
northeast NE between 15Z and 18Z...and the lift ahead of the
elevated warm front likely helped spark the TSRA with hail that
quickly moved into SD. This initial wave of H7 warm air advection
continues to move into MN and IA this afternoon.
This afternoon...the latest subjective surface analysis has the
warm front lifting across the forecast area with showers and
thunderstorms ahead of it. There has been a lot of lightning with
the storms and even some grass fires, however not a lot of
precipitation. Temperatures south of the warm front have warmed
into the mid and upper 60s with dewpoints in the 50s.
The large mid-tropospheric trough over NV/CA is forecast to shift
toward the four-corners area then deepen over CO/wrn KS overnight
into a closed low...slowly tracking across Kansas. Broad surface
low pressure over eastern Colorado further deepens tonight with a
cold front extending into central and northeast Nebraska.
The day1 severe weather outlook tornado probabilities extend from
central Nebraska into western Kansas south through the OK Panhandle
and the TX panhandle with an area of hail/wind outlook in this
similar area where thunderstorms will be more focused. Broad upper
level divergence and warm air advection along with PWATs around an
inch to 1.25" are progged.
The combination of the the approach of the upper level trough/broad
upper level divergence/waa/mid-level frontogenesis have isolated to
scattered storms this afternoon...becoming more focused from western
Kansas into western and central Nebraska into northeast Nebraska
this evening and tonight where CAPES of 1000-2500 J/kg will be more
prevalent and 0-6km bulk shear is forecast to exceed 60kts. The
RAP/HRRR did not have a good handle on the morning convection and
started to pick up on the afternoon convection with the 16Z HRRR
The general trend is to increase precipitation coverage from
central Nebraska into northeast Nebraska this evening and
overnight. Will maintain highest pops in northeast Nebraska
through tonight and Friday morning. Another area of showers and
thunderstorms ahead of the dry slot develops from eastern
Oklahoma into eastern Kansas and western Missouri and should make
it into southern Iowa friday. In between, scattered
showers/thunderstorms will be possible. The day2 SPC outlook
brings the marginal risk toward FNB...however keeps the slight
risk generally from southeast KS into southwest MO. Rain/showers
will continue on the northwest side of the storm system across the
outlook area Friday night and Saturday with the slow-moving
system.
Related to the rainfall expected...trimmed back amounts somewhat
with general amounts of a tenth to 0.50 inch. Still have higher
amounts from .75 to 1.75 for parts of northeast Nebraska.
.LONG TERM...(Sunday night through Thursday)
Issued at 320 PM CDT Thu Mar 23 2017
Unsettled weather continues with more showers Sunday
night...Tuesday night-Thursday. Highs mostly in the 50s and 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 606 PM CDT Thu Mar 23 2017
Main concern is deteriorating conditions associated with areal increase
of TSRA over ern Neb tonight. At this point...expect convection
currently organizing from NW KS into cntrl Neb along sfc trof/dry
to move into NE Neb later this evening and generally persist into
Friday morning. As for KOMA/KLNK...trends over the last several
hours combined with latest model guidance all suggest very low
chance for seeing TS activity thru the fcst pd.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...DEE
Area Forecast Discussion
National Weather Service Pocatello ID
200 PM MDT Thu Mar 23 2017
.SHORT TERM...Tonight through Monday.
Expect light showers in southeast corner to dissipate overnight
with dry weather expected through Friday morning. The next Pacific
system will begin to affect the region Friday afternoon with rain
and snow showers moving into the central mountains and spreading
east Friday night. Snow levels are expected to begin around 6500
feet and locations above that level may see 2 to 6 inches above
that level. Rain is expected below 6000 feet. Precipitation should
taper off Saturday afternoon with only light showers mainly in
the eastern highlands. Sunday should be mainly dry with another
Pacific system expected to spread precipiation over the entire
region Sunday night into Monday with snow levels again in the 6 to
7 thousand foot range expected. Temperatures are expected to
remain near seasonal normal Saturday through Monday after likely
well above normal highs on Friday.
GK
.LONG TERM...Monday night through Thursday. GFS and ECMWF remain
similar on timing of major features through east Idaho but differ
significantly on how those features look and act. Trough axis
drives through the region Monday night into Tuesday, amplifying
into split system with low close off somewhere in the vicinity of
the four corners region. The models really struggle with where
this low center closes and how it moves east. Upper flow remains
progressive however with weak ridge/high pressure Tuesday
night/Wednesday. Next system drives across the region Wednesday
night and Thursday, again following a split but again with major
differences on what the split does. Given the uncertainty in the
details, kept overall blend going through the period, but with
some confidence in general timing of precipitation trends. DMH
&&
.AVIATION...Low clouds have been stubborn to break up in at a couple
of the terminals but clearing line is slowly working southeast. HRRR
has been trying all day to generate some very weak showers KIDA/KPIH
and shifting this region southeast through the evening. Given recent
days performance of the HRRR am skeptical but weak instability along
edge of clearing line would be a common point for convective
initiation this afternoon. Added VCSH with 18Z run but also trended
cloud decks toward or continued VFR conditions. Could see some low
stratus return tonight, generally KPIH/KIDA/KDIJ where cloud cover
has been stubborn this morning. DMH
&&
.HYDROLOGY...Snowmelt flooding continues. High flows into dams along
the Bear River have necessitated additional releases from those
dams. The river remains high but below flood stage so issued a flood
advisory, especially with concern towards tributaries to the river.
The Bear River remains at or just above flood stage with downstream
affects at Pegram and beyond. Portneuf River remains above flood
stage. Otherwise all advisories remain intact where current
flooding exist or where trouble spots have been identified by
emergency management. Cooler temperatures the next several days
will likely slow, but will NOT cease, snowmelt runoff. Anticipate
flooding concerns to continue. DMH
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Friday morning for IDZ017>019-022>025-031-
032.
&&
$$
Area Forecast Discussion
National Weather Service Portland OR
837 PM PDT Thu Mar 23 2017
.SYNOPSIS...An occluding Pacific frontal system will bring
continued rain into southwest Washington and northwest Oregon
tonight, with showers and a few thunderstorms lingering into Friday.
High pressure will cause showers to taper off late Saturday, but the
next frontal system will likely bring more rain Sunday followed by
showers Monday. Occasionally wet weather is expected to linger
through the middle of next week.
&&
.SHORT TERM...Tonight through Sunday...Stratiform rain across the
area has dropped around 0.05" per hour for lower elevations and close
to 0.10" per hour in higher elevations in the Coast Range. This does
not warrant any adjustment to ongoing QPF forecast which looks pretty
good based on those rates. Latest satellite representation supports
HRRR which shows renewed development continuing overnight and into
tomorrow morning. The back edge of the precip will slowly slide east
of the area sometime tomorrow morning.
This is when conditions will need to be closely monitored for thunder
potential. Some dry air will come in behind this precip and may be
sufficient enough to scatter out clouds and get some sun. If this
does occur, at least some surface based instability will develop. Any
instability will be sufficient for thunder given the falling heights
and colder air aloft. In fact, given freezing levels are expected to
be around 4000 feet, it won`t take much of an updraft to form small
hail. If surface instability strengthens enough for updrafts to
extend beyond 10 kft (would guess around 400 to 500 J/kg), would
expect a few hail showers which may even lead to minor accumulation.
This all depends on the amount of clearing we get tomorrow
morning/afternoon, but the likelihood of clearing is high enough to
warrant a mention of the hail potential. As a result, expanded the
area of thunder slightly eastward and added a slight chance of small
hail for all areas north of Salem. These storms will be pretty
shallow. The effective shear will be significant enough, (25-30 kts)
to organize any stronger updrafts for hail formation, but these
shallow storms will lack the depth for any significant wind creation
either from evaporative cooling or water loading in the updraft. In
addition, extended thunder mention through 06Z as latest 3km NAM does
not bring the trough/cold front through the area until that time and
still has some convective elements along it as it moves through.
/Bentley
.LONG TERM...Sunday night through Thursday...12z global models are
in general agreement with evolution of the long wave pattern,
however, details are far too sketchy to pin down specific dry
periods. This is somewhat of a shift from earlier runs where the
early part of next week showed signs of a brief dry period. COld
front Sunday night will push east through early Monday. Plenty of
orographic showers will follow through Monday evening. There, the
GFS and ECMWF start to show differences among the operational runs.
Have thereafter decided to stick fairly close to a blend of the
ensemble means as the ECMWF is slightly more progressive with the
westerly flow while the GFS is continuing more of the amplified
pattern it`s shown the last few days. The 12z runs do come back
together on Wednesday/Wednesday night with a trough sweeping east
across the region. For now, that looks like the wettest day although
given the run to run inconsistency, have kept lower end likely pops
for now. Regardless of the details, overall conditions will close to
seasonal temperature norms which keeps snow levels bouncing between
4000 and 6000 feet. /JBonk
&&
.AVIATION...Conditions have remained VFR so far this evening both
at the coast and inland as rain has spread over the area with the
incoming front. Still think MVFR is possible before the front
moves onshore along the coast 08z-10z and through the inland by
10z-12z. Conditions will then try to lift back to VFR behind the
front though showers in the onshore flow behind the front may
drop conditions at times to MVFR. In addition, there is a chance
of thunderstorms at the inland TAF sites Friday afternoon as
cooler air aloft spreads in behind tonight`s front.
KPDX AND APPROACHES...VFR conditions with rain through much of
tonight, with a chance of MVFR conditions. VFR conditions will
then tend to prevail on Friday with a chance of MVFR in any
heavier showers, and with a chance of thunder in the afternoon.
pt
&&
.MARINE...A strong cold front is over the coastal waters this
evening, with a peak gust at buoy 50 to 43 kt so far. The models
continue to say the front will move onshore a little after
midnight. The south winds will drop off to Small Craft Advisory
values late tonight and Friday morning, then turn more
southwesterly Friday afternoon, then turning even more westerly
and finally dropping below 20 kt overnight Friday night. The
next significant winds are expected with another rather strong
front Sunday. Look for high end Small Craft Advisory winds or low
end gales with the Sunday front.
Seas continue to be forecast to peak around 16 ft tonight, and
with the way our wave models perform it could be a couple of feet
higher. Seas are then forecast to drop to around 10 or 11 ft
during the day Friday and continue near those values through much
of Saturday, dropping below 10 ft late Saturday and Saturday
night. Seas will likely exceed 10 ft Sunday with the next front.
pt
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Gale Warning until 1 AM PDT Friday for Waters from Cape
Shoalwater WA to Florence OR from 10 to 60 nm.
Gale Warning until 3 AM PDT Friday for Coastal Waters from Cape
Shoalwater WA to Florence OR out 10 nm.
Small Craft Advisory for Rough Columbia River Bar until 6 AM
PDT Friday.
Small Craft Advisory for Rough Columbia River Bar from 1 PM to
6 PM PDT Friday.
&&
$$
Interact with us via social media:
www.facebook.com/NWSPortland
www.twitter.com/NWSPortland
This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. The area is
commonly referred to as the forecast area.
Area Forecast Discussion
National Weather Service Raleigh NC
850 PM EDT Thu Mar 23 2017
.SYNOPSIS...
Cool high pressure over the East Coast will shift offshore late
tonight, allowing a warm front to lift north across our region on
Friday. Warm southerly flow will persist into the weekend. A passing
upper level trough will bring a chance of showers late Saturday
night through Sunday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 850 PM Thursday...
The surface high centered just off the Mid Atlantic coast this
evening will continue drifting to the NE while extending SW through
central NC. While the low level flow will become more easterly and
southeasterly overnight, with a weak inverted trough forming just
off the Carolina coast, the flow will be very light which will limit
recovery of current very low dewpoints overnight, although they`ll
climb most in the SE. Observed 00z sounding show fairly dry air in
place, although based on the mid level flow and RAP depictions, the
area of mid and high clouds extending from IN across KY/E TN/NE GA
should pivot more N-S and drift eastward overnight, yielding a trend
to partly cloudy skies over the NW CWA, with mostly clear skies
elsewhere. Expect lows in the low-mid 30s except for some upper 20s
in the NE under cloud-free skies with light winds. -GIH
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 315 PM Thursday...
Friday...Upper level ridge axis currently extending along the spine
of the MS Valley will drift over the Southeast U.S. by Friday. Warm
air advection on the back side of the 850-500mb ridge currently
supporting a band of precip across the lower OH Valley into the TN
Valley early this afternoon. This precip area is farther south than
projected by most of the near term and CAM progs. Latest HRRR
depicts this band of mostly light precip dissipating as it lifts ewd
toward the Smoky Mtns.
Increasing low level sly flow will tap moister residing to our south-
sw which should led to scattered patches of cu, especially across
the southern coastal plain, and into the western Piedmont. The rest
of the column will remain dry, so precip chances will remain below
20 percent. The warming air mass and low level sw flow will push
temperatures back to normal levels, primarily in the 65-70 degree
range.
Milder temperatures anticipated Friday night as sly low level flow
continues and atmosphere continues to moisten. There will be a
greater probability for low stratus to develop after midnight.
Overnight temperatures in the mid-upper 40s.
&&
.LONG TERM /Saturday through Thursday/...
As of 240 PM Thursday...
High confidence in warm weather through the early part of next week,
with bouts of showery weather, primarily on Sunday and Tuesday.
Uncertainty grows midweek and beyond as differences emerge regarding
their handling of polar low deepening over SE Canada and the
adjacent NW Atlantic waters, however it appears certain that the
wavy active southern stream pattern will persist through next week.
Sat/Sat night: The potent mid level low will cross the central Miss
Valley as its southward-extending trough takes on a negative tilt
over the Mid South and Gulf States, leading to strengthening mid
level flow from the SW into the Carolinas. PW will remain elevated,
in the 75th percentile, with a light onshore-directed southeasterly
flow drawing in increasing low level moisture. We should see
considerable morning stratus and fog, particularly over the western
half of the CWA where low level moist upglide will be deepest, and
these clouds should lift to scattered to broken stratocumulus (more
clouds west than east) with heating, and these should persist
through the day, topped with high thin clouds. Very dry/stable mid
levels will keep the day mostly dry, apart from possible patchy
morning drizzle in the western Piedmont. Thicknesses will continue
to trend above normal, supporting highs of 70-76 NW to SE. The mid
level low tracks slowly from MO to IL Sat night, bringing the
negatively tilted trough axis and its DPVA into the western
Carolinas. This southerly steering flow will drive up PW to nearly
200% of normal just to our west and into the far NW Piedmont late
Sat night, in tandem with the arrival of 25-35 kt low level jetting
into the Srn Appalachians. Will bring in good chance pops very late
Sat night into the far W CWA. Lows Sat night mainly in the mid 50s.
Sun/Sun night: The mid level low will quickly weaken and fill as it
approaches Lower MI Sun, while the trailing trough axis pivots
northeastward through our area. The best precip chances (likely to
categorical) will track ENE through central NC (especially NW) Sun
morning into early afternoon beneath a band of enhanced upper
divergence, with PW rising further to 250% of normal as steering
flow becomes southwesterly. Despite the moist column, the dwindling
dynamic forcing for ascent as this system tracks NE through the Mid
Atlantic region will lead to a tapering down of precip chances
through Sun, especially over our SE sections, as the core of the
peak integrated water vapor transport shifts to our NNE. Only low
chances are expected Sun night as the dampening mid level trough
axis shifts to our NE with gently rising heights aloft, within a
continued very moist column. Expect highs of 70-78 followed by lows
in the upper 50s with overnight stratus developing.
Mon-Tue: Monday will feature just patchy light precip at most over
much of central NC as a mid level ridge axis shifts overhead with a
weak cap at 925 mb and dry mid-upper levels, although higher PW
settling over eastern NC and higher surface dewpoints may prompt
greater convection coverage over our SE. Our next mid level trough
in this active pattern will push through the eastern third of the
CONUS Mon night through Tue, accompanied by a surface cold front.
Important model differences start to emerge, with the GFS slower and
more amplified than the weaker/faster ECMWF. Will lean toward the
more progressive ECMWF given this active pattern, but confidence is
not high. Will maintain good chance of showers and storms Mon night
through Tue. Highs 75-80 Mon/Tue with thickness over 35 m above
normal. Lows in the upper 50s.
Wed-Thu: Model details differ, but in general, heights will rise
over the Southeast in the wake of the departing trough, as another
powerful and deep low tracks over the Southwest states. Expect dry
weather and cooler temps, still near or just above seasonal normals,
as surface high pressure builds in from the north. -GIH
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 740 PM Thursday...
24 Hour TAF Period: High confidence in VFR conditions through the
TAF period, with the exception of an outside chance of some MVFR
visibility restrictions at KRWI and KFAY just before sunrise. Calm
winds overnight becoming southwesterly near 10 kts with potential
for wind gusts of 15-20 kts during the afternoon hours. Some high
clouds possible early in the TAF period with scattered clouds around
5 kft developing Friday afternoon.
Long term: As the weekend progresses, better chances for early
morning fog/low stratus will prevail with best chance for
significant precipitation occurring in the northwest Piedmont on
Sunday evening with a more progressive frontal passage early to the
middle part of next week.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...WSS
LONG TERM...Hartfield
AVIATION...LT/Ellis
Area Forecast Discussion
National Weather Service Charleston WV
1027 PM EDT Thu Mar 23 2017
.SYNOPSIS...
Warmer weather returns as southerly winds pump air from the Gulf of
Mexico. Temperatures will climb well above normal this weekend. the
next shot at showers arrives Sunday morning.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1025 PM Thursday...
RAP and HRRR keeping the precipitation out of the northern zones
tonight, but will leave the low end POPs on the northern fringe
given the warm frontal characteristics.
As of 705 PM Thursday...
Only minor changes this evening. Expecting cloud cover to
increase tonight, with overnight low temperatures much milder
than last night.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 100 PM Thursday...
A deepening mid level cyclone in the midwest will continue to churn
and move slowly north northeast through the short term. This will
keep the region in the warm sector and largely precip free. With
southerly flow in the low levels of the atmosphere, H8 temps climb
into the double digits. This will equate to the warmest weekend
since the last week of Feb as the mercury makes a run near 80F in
the coal fields, but mostly 70s outside the higher terrain. The
occluded front is knocking on the door of the tri state region
around Huntington by 12z Sunday. Continue to ramp up probability of
precip chances by then, however given the strength of this system
would expect a later onset as we get closer due to operational model
bias.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 100 PM Thursday...
Highlights:
- Above normal temperatures and precipitation
- Dry spells won`t be that long
- No big storms
Active southern stream will yield a parade of weather systems moving
across the region. With all of the low pressures passing well to
our northwest and the Gulf wide open, no signs of winter weather on
the horizon.
Monday and Tuesday yield the warmest weather of the week as
temperatures climb 15 to 20 degrees above normal. I would not be
surprised to see a few places in the southern coal fields get to
80F. Nonetheless, most of the tri state will be basking well into
the 70s. The higher elevations will be in the 60s, still above
normal for late March. The weather gets iffy mid week with the
placement of a baroclinic zone somewhere in central WV / I-64
corridor. This will bring temps back to reality due to clouds and
scattered showers.
A transitory mid level anticyclone crosses Thursday and Friday which
will a return of dry weather.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
As of 705 PM Thursday...
VFR through the period with mid level moisture from a warm front
passing through tonight, lowering to low end MVFR between
3-4kft. Surface flow less than 10kts out of the south/southeast.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: High.
ALTERNATE SCENARIOS: None.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 03/24/17
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H H H H H M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY H H H H H H H H H H H M
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 00Z SATURDAY...
Restrictions and low level wind shear are likely with the
advance of late Monday cold front.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...TRM/SL
NEAR TERM...26
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...26
Area Forecast Discussion
National Weather Service Blacksburg VA
1002 PM EDT Thu Mar 23 2017
.SYNOPSIS...
High pressure will slide off the coast tonight into Friday. A
warmer southerly flow will develop Friday into the weekend ahead
of a slow moving cold front that will approach the region
Sunday. A series of upper-level low pressure areas will track
across the central and southern U.S. through next week keeping
an unsettled weather pattern in place.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1002 PM EDT Thursday...
Update to lower forecast low temps across the western valleys and
out east given lingering very dry air per evening soundings and
latest obs. This in conjunction with possible development of a weak
bubble of high pressure over the east given ridging aloft, likely to
allow good radiational cooling again tonight despite 850 mb warming
as well as slowly rising dewpoints. Also band of broken mid/high
clouds just west of the mountains likely to fade initially upon
encountering the very dry air aloft so appears will stay clear
longer espcly eastern half. Again expect some 20s in the western
valleys and perhaps outlying areas across the east with overall
low/mid 30s elsewhere, except around 40 across the higher
ridges where better warm advection mixing will occur.
Previous update as of 705 PM EDT Thursday...
Forecast looks to be in pretty good shape through the next few
hours, as clear skies for the first part of the evening allowing
for temperatures to plummet quickly after sunset. I did make
some changes for the late evening into the overnight period.
Leading edge of warm front and a broken to at times overcast
mid-level cloud shield extends roughly NNW- SSE from northern
Illinois southeastward to the eastern Tennessee Valley. This
cloud shield should advance eastward into our western counties
around midnight and continue lifting in a northeastward fashion
across the New River/Roanoke Valleys into the southern
Shenandoah counties overnight, as reflected in past couple RAP
model 700-300 mb RH profiles. Though Virginia Southside towns
into the NC foothills and Piedmont probably stand to radiate
fully the whole night...given that the clouds may be thick
enough to impede or stop radiational cooling entirely elsewhere,
I`ve utilized some of the warmer temperature guidance after
midnight to reflect a slower cooling in cloudy areas. Dewpoints
were also raised upward some overnight, accompanying the
increase in clouds. In the Grayson Highlands and the NC High
Country dewpoints are already on the rise from low afternoon
values are now into the low to mid 20s. Given the trend in cloud
cover, lows in the western counties probably reach lows in the
mid 30s earlier with overnight lows occurring closer to sunrise
in the Piedmont and Southside areas.
Previous near-term discussion issued at 214 PM follows...
Dome of high pressure along the east coast is going move offshore
tonight into Friday allowing for the area to move into warm
advection. Expect temperatures to drop again tonight to the upper
20s to lower 30s in the east and mountain valleys, except mid to
upper 30s across the higher terrain in the west with southerly winds
picking up more.
Late tonight through Friday, models are showing increasing moisture
in the mid and upper levels tracking from KY/TN into the mid-
Atlantic with some light precip being generated north of our
forecast area. Anticipate some increase in clouds late tonight into
Friday mainly over the west and north, but still looking at more
sun than clouds Friday as temperature warm into the 60s, except some
50s along the Blue Ridge.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 345 PM EDT Thursday...
A pattern transition will be underway this weekend as
predominate northwest flow aloft comes to an end, replaced by
unsettled split flow with series of southern stream storm
systems of Pacific origin to parade across the CONUS. First in
this series of storm systems will arrive Sunday. Until its
arrival, the first half of the weekend will be dry, Saturday
certainly a great day to be outdoors with temperatures in the
60s/70s.
Late Saturday, moisture will be on the increase west of the
Appalachians per the approach of an upper low to lifting out of
the Southern Plains. Showers/thunderstorms associated with this
system will be advancing east across the Tennessee Valley into
far southwest VA or southern WV Saturday night. The upper low
will then take a more northward track into the Ohio Valley and
weaken as it encounters the upper ridge along the eastern
seaboard. This will result in a weakening of the thunderstorm
activity as it crosses the mountains, but still sufficient
forcing, instability, to promote high probability of showers
areawide for Sunday. Temperatures Sunday will be just a tad
lower thanks to cloud cover and precipitation, but with
increasing dewpoints, overnight lows will be warmer.
With regard to QPF, models are in fairly good agreement,
advertising 1/2 to 3/4 inch of rain along and west of the Blue
Ridge Sunday, and 1/4 to 1/2 inch east of the Blue Ridge.
Severe weather is not expected for our CWA for this first
system.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 400 PM EDT Thursday...
Next in a series of upper-level low pressure areas will move
from the Southern Plains into the Tennessee Valley/Central
Appalachians late Monday into Tuesday. While this system will
again be weakening as it moves toward the western Atlantic upper
ridge, it will have somewhat better dynamics and instability to
work with than the Sunday system. Therefore, a chance of
thunderstorms anticipated areawide for Tuesday afternoon. This
still does not look like a widespread severe weather maker for
our CWA, but slightly better potential for at least some
stronger storms with small hail per warmer temperatures, higher
surface dewpoints and slightly better instability compared to
the Sunday system. Rainfall amounts again appear to be in the
1/4 to 3/4 inch range over all with this event.
A quieter midweek period appears in order as another upper-
level system deepens but slows as it moves into Texas and an
upper ridge amplifies across the eastern U.S. A weak area of
high pressure from the Great Lakes filters into the area for
midweek. By Friday, this aforementioned system will move into
the Mid-Atlantic region as yet another upper-level low pressure
area moves from the southwest U.S. into Texas.
Temperatures will remain mild through the upcoming week with no
significant intrusions of Canadian air. A slight cooling will
be noted midweek, but temperatures will favor the warm side of
normal with highs in the 60s/70s and lows mainly in the 40s to
lower 50s.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
As of 709 PM EDT Thursday...
VFR through the period. Initial SKC conditions give way to a BKN
mid-level altostratus deck after 06z and then lifts into
northern Virginia by mid-morning. Should see VFR FEW-SCT cumulus
in the warm sector the rest of the day. Winds light southeast
tonight, then veer and increase to south 5-10 kts, strongest at
Lynchburg and Danville.
Extended Aviation Discussion...
Good flying weather is expected to linger into Friday night before
moisture starts to increase over the weekend ahead of an upper-
level low pressure area moving northeast from the Southern
Plains. Precipitation is not expected until Sunday when sub-
VFR conditions become more of a possibility. Otherwise looking
at overall VFR to start the weekend with most lower cigs
remaining west of the area until later Sunday at this point.
Periods of unsettled weather will continue into the first half
of next week as a series of upper-level lows track from west to
east across the U.S.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...KK/WP
NEAR TERM...AL/JH/WP
SHORT TERM...PM
LONG TERM...PM/RAB
AVIATION...AL/RAB/WP