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FXUS62 KRAH 200126

Area Forecast Discussion
National Weather Service Raleigh NC
926 PM EDT Tue Sep 19 2017

A weak upper level trough will move into the area on Wednesday and 
will linger while gradually dissipating through the end of the week. 


As of 925 PM Tuesday...

Quiet weather as central NC sits between Hurricane Jose which is 
spinning off of the Delmarva Peninsula this evening and a short wave 
moving through eastern TN and northern GA. Calm winds and clear 
skies will prevail overnight with some MVFR fog possible across the 
north and possibly at KRWI. Overnight lows will be in the middle 60s 
with a few lower 60s possible due to the great radiational cooling 


As of 307 PM Tuesday... 

A weak shortwave upper trough, comprised of several individual 
shortwaves that currently extend from the Ohio Valley SW into the 
Middle/Lower MS Valley will progress slowly ESE, moving into Central 
NC  Wednesday afternoon and evening, before stalling out near the 
NC/SC late Wednesday night and Thursday. Limited by the lack of 
support/lift in the low-levels and the deep NWLY flow preceding the 
trough, convective coverage should be no greater than isolated to 
widely scattered Wednesday afternoon and evening, and largely driven 
by daytime heating. Weak deep layer shear of 10 kts or less coupled 
with MLCAPE values of 700 to 1500 MLCAPE will keep any convection 

The real story on Wednesday will be the return of near to 90 degree 
heat across central and southern portions of the state as low-level 
thicknesses and H8 temps increase to 1420-1425 meters and 17-18 C 
respectively. This should support highs a full category warmer than 
today, with highs ranging 85 to 90. Lows in the mid to upper 60s. 


As of 235 PM Tuesday...

Lingering troffing in the wake of Jose across the Carolinas will be 
pushed slowly south Thursday and Friday. This will potentially 
produce scattered showers across the southern tier of central NC 
during peak heating, during which highs will reach mid and upper 80s 
with perhaps some very low 90s. 

A surge of drier and modestly cooler air will advect south (hard to 
call it a front) late in the day Friday, cooling temperatures back 
to the low and mid 80s and lowering the chance of precipitation to 
the single digits through the weekend. This pleasant airmass will 
remain in place, reinforced by low level flow veering gradually 
northeast as Maria lifts up the Atlantic coast. Maria's official 
track does not bring the storm near enough to produce any sensible 
weather impacts to central NC other than perhaps some gustiness and 
bands of showers into the Coastal Plain Tuesday.  


As of 820 PM Tuesday...

The low level flow will continue to become increasingly wly on the 
back side of Tropical Cyclone Jose, which will result in a much 
lower probability of sub-VFR conditions relative to previous days. 
Only patchy MVFR visibility restrictions in fog are expected late 
tonight-early Wed, mainly at RWI, and perhaps INT/GSO. Otherwise, 
the approach of a mid to upper level trough, and associated pocket 
of colder temperatures aloft, may result in the development of a few 
showers late Wed and Wed evening, mainly in the vicinity of Triad 
TAF sites. 

Outlook: Generally VFR conditions are expected. The exception will 
be a chance of mainly MVFR fog Thu and especially Fri mornings, 
mainly at FAY and RWI.  





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