Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kakq 271740 

Area forecast discussion
National Weather Service Wakefield Virginia
1240 PM EST Mon Feb 27 2017

high pressure slides offshore today ahead of a warm front, which
lifts through the region tonight into Tuesday. Broad southwest flow
will allow temperatures to warm well above normal Tuesday and
Wednesday. A strong cold front approaches from the west Wednesday
and crosses the region Wednesday night.


Near term /until 6 PM this evening/...
high pressure is across the ern Carolinas into southeast Virginia
early this morning with high clouds arriving from the west.
Temperatures have dropped into the upper 20s to low 30s, with
mid/upper 30s for coastal southeast Virginia/NE NC. These values seem much cooler
given recent warmth, but are actually around seasonal averages.
Clouds increase today (especially n) as the surface high moves
offshore and warm air advection aloft commences. Additionally moisture begins
streaming into the region from the southwest in strong zonal flow.
The forecast remains dry with temperatures generally warming into
the lower 60s (upper 50s far nrn counties and Maryland/Virginia eastern shore).


Short term /6 PM this evening through Wednesday night/...
a warm front is progged to lift through the region
tonight into Tuesday morning as a broad mid/upper ridge builds over
the ern conus. Cloud cover increases across srn Virginia/NE NC along with
sct showers for coastal southeast Virginia/NE NC in vicinity of a coastal trough,
mainly after midnight. Much milder tonight with lows ranging from
the mid 40s north/NE to low 50s southeast. Partial clearing is possible across
the nrn zones, and if this occurs lows could drop into the low 40s.

The warm front lifts north of the region Tuesday into Tuesday night.
There will be minimal forcing for any showers within the warm sector
and lapse rates and instability are marginal at best, so no thunder
is expected at this time. Pops will generally be aob 20% Tuesday
through Tuesday night, although the 27/00z GFS/European model (ecmwf) show an impulse
tracking across the top of the ridge Tuesday evening, so a 30-50%
pop is forecast for far north/NE portions. Much warmer Tuesday with
highs ranging from the upper 60s north to the low/mid 70s southeast (low 60s at
the immediate coast of the ern shore). Mild Tuesday night with lows
in the upper 50s to low 60s, with some patchy stratus possible late
Tuesday night into early Wednesday morning.

Strong warm air advection continues into Wednesday with 850mb temperature rising to
+12-15c. Meanwhile, a strong cold front is progged to reach the
Appalachians by later Wednesday aftn. A chc of showers will linger
NE in the morning, but much of the area should be dry late morning,
through mid-aftn. Becoming partly sunny and breezy, with a south-southwest wind
potentially gusting up to 30-35 mph during the aftn. Very warm with
high temperatures rising into the upper 70s to around 80 (locally
cooler at the immediate Atlantic coast of the ern shore). The 27/00z
European model (ecmwf) seems a rather good compromise for frontal timing, Wednesday
evening as it is a Mid-Point between the faster GFS and slower NAM.
Likely pops for showers/tstms spread across the area Wednesday
evening and then taper off northwest-southeast after midnight as cooler/drier air
arrives from the northwest. The flow aloft will be very strong in vicinity
of the front, up to 140kt at 200mb, and 70-80kt at 500mb. This will
yield 0-6km bulk shear values of 50-60kt. However, 850-700mb lapse
rates are marginal, and the strong SW flow may shunt the best
instability offshore prior to the arrival of tstms. The wind field
alone will result in a slight risk for severe tstms. However, at
this time the synoptic/kinematic/thermodynamic factors do not seem
to line up as well as last Saturday, so the same classic storm
organization is not expected at this time.


Long term /Thursday through Sunday/...
an active northern stream with a west to northwest flow will bring a
few days of cooler weather late in the week.

An upper trough will spread over the ern conus Thursday, with
the front pushing offshore and much cooler 850mb temperatures
arriving (-2 to -5c). A weak short wave will bring a small
chance for rain (20 to 30 percent) Friday over northeast
portions of the area (mainly Northern Neck and lower eastern
shore). This will enhance the cooler air aloft with 850mb
temperatures dropping to -6 to -10c by 00z Saturday.

Temperatures will be closer to normal during the long term than
those of the recent past. Temperatures will lower Thursday through
Saturday then warm some on Sunday. Highs in the 50s to around
60 Thursday and lower to the mid 40s to lower 50s by Saturday
then increase to between 60 and 65 Sunday except 50s along the
coast. Lows in the upper 40s to mid 50s Thursday morning lower
to the 30s the rest of the week with some upper 20s inland areas
Saturday morning.


Aviation /17z Monday through Friday/...
high pres remains offshore this aftn with S/SW flow avgg 8-10
kt. Mid to high clouds continue to stream into the area from the
west, and this will continue through the taf period. A weak
coastal trough will be near the Carolina CST late tngt, which
may produce a few showers across far eastern areas of the fa.
The chance is too low however attm to include mention in the
18z tafs.

Outlook...a warm front lifts north through the region Tuesday with
only a minimal chc of showers Tuesday/Tuesday night, aside from
a 30-50% chc for sby Tuesday evening. A strong cold front will
approach the region from the west on Wednesday, cross the region
Wednesday evening, and push offshore late Wednesday night. This
cold front will bring showers/tstms likely Wednesday
evening/night. High pressure returns Thursday and Thursday
night, followed by a secondary, mainly dry cold front Friday.


early this morning, high pressure was cntrd just off the mid
Atlantic coast, providing south-southeast winds 5 to 10 kt, waves 1 to 2 ft
and seas 2 to 3 ft acrs the waters. The high will slide farther
out to sea today into Wed, resulting in a gradual increase in S
then SW winds over the waters. The next sca's will be Tue night
or Wed acrs most of the waters, in advance of the next strong cold
front. That cold front will then cross the waters Wed night into
early Thu morning, with sca's continuing for most of the waters
Wed night into Thu aftn, with the frontal passage and Post
frontal northwest winds.


Feb 2017 is shaping up to rank among the warmest on record
given continued warmth over the next week. Shown below are the
top 3 warmest february's on record. Expecting ric and orf to be
the 2nd warmest and for ecg to be at least within the top 3
warmest. Sby looks on track to be the 4th or 5th warmest.

Warmest february's on record (average temps):

* ric: (most likely finish for 2017: 2nd warmest)
1) 49.9 (1890)
2) 48.5 (1976)
3) 48.1 (1884)

* orf: (most likely finish for 2017: 2nd warmest)
1) 52.4 (1890)
2) 50.5 (1909)
3) 50.1 (1990)

* sby: (most likely finish for 2017: 4th warmest)
1) 46.1 (1976)
2) 45.8 (1984)
3) 45.7 (1925)

* ecg: (most likely finish for 2017: 3rd warmest)
1) 52.1 (1990)
2) 51.8 (1939)
3) 50.3 (1976)


Akq watches/warnings/advisories...


near term...ajz
short term...ajz/mrd

National Weather Service Glossary of Abbreviations