Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/19/16
Area Forecast Discussion
National Weather Service Melbourne FL
909 PM EST Sun Dec 18 2016
Scattered showers a few lightning storms moved NE from Osceola
county toward Orlando and nrn Brevard and Srn Volusia county into
late evening. Latest HRRR indicates convection should continue to
move NE through midnight and then start to dissipate. Will continue
some low convective chances thru midnight and then expect fog and
stratus to develop into the late night hours mainly across nrn and
interior sections with light southerly low level flow ahead of a
slow moving front across the FL panhandle. There could be some
locally dense fog in spots across the nrn interior late tonight
though around sunrise. Lows will be mild from 65-70.
Update...Little change to current CWF with southerly winds
decreasing to around 10 knots overnight. Seas 3-4 ft near shore
up to 4-5 ft well offshore. No headlines needed.
Tonight-Monday.. Winds/seas over the marine area will continue to
decline as gradient ascd with high pressure well east of the state
shunts farther Ewd over the open Atlc. Sly winds of 10 to 15 kts
this evening will reduce to around 10 kts by early Mon. Winds Aob 10
kts are expected Mon with an onshore breeze developing along the
Daytona Beach has set a new daily record high of 86 degrees,
breaking the old record of 84 in 1961. If everything holds for the
rest of the day today, all four climate sites will at least tie daily
record warm minimums. The current low is 68 for Daytona Beach which
would tie the current record set in 1961. Orlando International
Airport only dropped to 67 this morning which would tie its record
also set in 1961. Melbourne would set a new daily record warm minimum
of 69 degrees breaking the current record of 68 set in 1961. Vero
Beach is on pace to tie its daily record warm low of 71 set in 2006.
Local warm temperature records Today-Monday:
LOC DATE HI-MAX HI-MIN
DAB 18-Dec 85 2017 68 1961
MCO 18-Dec 90 1961 67 1961
MLB 18-Dec 88 1961 68 1961
VRB 18-Dec 86 1961 71 2006
DAB 19-Dec 87 1990 67 1931
MCO 19-Dec 88 1922 68 1961
MLB 19-Dec 84 1990 68 1961
VRB 19-Dec 85 1990 70 2006
Area Forecast Discussion
National Weather Service Blacksburg VA
925 PM EST Sun Dec 18 2016
A cold front will continue to push east of the region overnight
into early Monday allowing a large area of high pressure to slide
in from the west through the middle of the week.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 855 PM EST Sunday...
Cold front is now south and east of the area with the evening RNK
sounding showing quite a bit of dry air in the mid levels mainly
between 500-800 mb attm. Expect this to continue to advect east
overnight but likely wont be able to push the deeper moisture out
of the far southeast as yet another wave ripples up the boundary
per latest water vapor loop. In fact the latest HRRR and 00z Nam
bubble light rain back into southeast sections after midnight so
plan to leave in some low pops there overnight. However appears
deeper cold advection wont be able to catch up with much of the
moisture, but could be close for spotty freezing rain/drizzle
pending how far north the precip returns and how close to
freezing surface temps get. Since quite uncertain with both will
leave out any icing mention for now. Otherwise expect mainly
cloudy skies overnight with perhaps some breaks east of the
upslope western zones later and across the northeast where drier
air may undercut by morning. Also appears moisture will remain too
shallow for western snow showers overnight but cant rule out some
spotty freezing drizzle across the ridgetops within the low
clouds. Gusty northerly flow at times should diminish some
overnight but still much colder with lows looking on track with
20s west to low/mid 30s east.
Previous discussion as of 235 PM EST Sunday...
At 245 pm, the surface front was moving off the Blue Ridge and
over the foothills counties of Virginia. Since the front has moved
east of the mountains and into relatively more stable air from
recent cold air damming yesterday, the overall coverage of showers
has become disorganized. However, a narrow line of organized
convection is forming along the front as it tracks across the
Carolinas. With the front and associated convection tracking to
the coast and cooler drier air filters in overnight, rain/snow
chance will be on a sharp decline starting this evening. The last
area that will see rain this evening will be across Southside VA
and northern Carolina piedmont.
Bufkit forecast soundings displaying cold air will arrive first
in the low levels. Since some warm air exist aloft and cold
northwest flow increases this afternoon and evening, some light
snow may fall and/or freezing drizzle since the layer is shallow.
Any accumulations will remain light with no headlines need.
Temperatures tonight will range from the 20s across the northern
and western CWA to the lower 30s across the southeast. Where skies
completely clear, there will be an opportunity to dip into the
teens...these sort of temperatures favoring the WV/VA Highlands.
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
As of 236 pm EST Sunday...
Upper trough slow to move across the area and will hang frontal
boundary aloft across the eastern Carolinas. Some overrunning may
spread into southside VA/Caswell County early Monday before
further upstream trough strengthens and kicks this system east.
Staying chilly Monday with highs in the 30s most locations, with
a northerly wind, mainly under 10 mph.
Should see clearing skies with high pressure building in for
Tuesday into Wednesday. Zonal flow will keep temps within a few
degrees of seasonal norms by midweek. Until then light surface
winds and clearing skies should allow temps to drop into the 20s
Monday night with some teens in the valleys.
Tuesday sees the wind flow turn more south but expect still cool
day with highs in the 40s.
By Wednesday highs will range from the mid to upper 40s west to
lower to mid 50s east as high pressure stays centered over the
southern Appalachians and Carolinas.
Some models showing precip arriving ahead of next front Thursday
morning but think drier air in place will keep main threat after
7am Thursday so keeping it dry Wed night with increasing clouds,
and lows in the 30s, though temps may rise toward dawn.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 100 pm EST Sunday...
Really only one system to deal with showers this period as models
are in enough agreement for sfc front to push east across us
Thursday. Appears fast enough flow aloft and speed of front will
limit amounts but will see best threat of showers during the day.
Question of ptype should be answered as looks like enough warm
advection ahead of this system to have all precip as rain. Colder
air and gusty northwest winds will arrive Thursday night with some
upslope component keeping the threat of rain to snow showers around
but will see low chance pops.
Friday-Saturday will be seasonably cool with highs in the upper 30s
to lower 40s west to mid 40s to near 50 east. Lows Friday morning
are expected to range from the mid 20s in the higher elevations to
lower to mid 30s east, then as high pressure works east the low
level flow appears to turn around to the southeast causing similar
temps area wide as mixing starts to bring warmer air into the west
late. Lows will generally be in the upper 20s to lower 30s, though
some lower to mid 20s possible across the deeper valleys.
As we head toward Sunday the flow aloft steadily increases from the
west southwest while at the surface, high pressure moves from the
Ohio Valley to the northeast U.S. A strong frontal system works
across the Central Plains toward the Mississippi Valley. Will start
to see clouds increase Saturday night and especially Sunday.
Question will be in how fast the low levels moisten up. A blend of
the extended models leads to slight chance of rain Sunday along the
Blue Ridge and southeast. Look for warmer temperatures but not too
much above normal Sunday with cold air wedge a possibility. Highs
will mainly run in the upper 40s to lower 50s.
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
As of 605 PM EST Sunday...
Cold front exiting to the east this evening will take the
remainder of the residual light precip out of the area overnight.
However may still see some upslope driven spotty snow showers or
patchy freezing drizzle around KBLF/KLWB through about midnight
before moisture becomes quite shallow. However dense freezing fog
along with mountain obscurations may linger overnight in these
areas where will maintain MVFR to IFR into early Monday. Otherwise
looking at a period of mainly VFR to the east of the mountains
this evening with MVFR along the Blue Ridge and points west. Bufkit
soundings then show some added lowering of cigs elsewhere espcly
southern/western sections after midnight as another weak wave
slides up the front to the southeast. This may be overdone but
given consensus with support from the HREF kept the trend of
keeping MVFR cigs at KBCB and perhaps including at KROA overnight,
with mainly low end VFR cloud bases across eastern sites.
Northerly winds will remain gusty at 15-25 kts this evening before
diminishing to around 10 kts overnight.
Guidance suggests that low level moisture will be slow to vacate
the western sites Monday while clearing in the east as a brief
wedge of dry air sinks in east of the Blue Ridge. Just how long to
keep sub-VFR cigs espcly KROA westward a bit uncertain as most
solutions hold low clouds in until around midday before scattering
out under a mid/high canopy. Thus plan to show improvement across
the mountains after midday with all locations becoming VFR early
to mid afternoon under a drier north/northeast trajectory at 5-15
Should then see mainly VFR Monday night as high pressure slides
closer and low level moisture becomes more limited.
Extended aviation discussion...
Weather conditions are expected to remain VFR for Tuesday into
Wednesday under high pressure. Next potential for sub- VFR is
Thursday associated with another cold front that will move from
west to east across the region. Precipitation associated with this
front is expected to be rain with perhaps a period of snow showers
and gusty northwest winds across the mountains Thursday evening.
Expect a return to overall VFR under diminishing winds on Friday
with high pressure building overhead.
The NOAA Weather Radio in Ashe county at Mt Jefferson remains off
the air tonight possibly due to phone line issues. Technicians
have been notified but the time that restoration will occur is
unknown at this time.