WPC Met Watch |
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Mesoscale Precipitation Discussion: #1057 (2022) |
(Issued at 324 PM EDT Fri Sep 30 2022
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MPD Selection |
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Mesoscale Precipitation Discussion 1057
NWS Weather Prediction Center College Park MD
324 PM EDT Fri Sep 30 2022
Areas affected...Northern South Carolina...Western North Carolina
Concerning...Heavy rainfall...Flash flooding possible
Valid 301920Z - 010030Z
SUMMARY...The western flank of Hurricane Ian will continue to
produce prolonged periods of heavy rainfall over South Carolina
and western North Carolina for several more hours, potentially
resulting in additional areas of flash flooding this evening.
DISCUSSION...Hurricane Ian made landfall near Georgetown, SC this
afternoon and its western flank continues to generate
moderate-to-heavy rainfall. 850mb winds over the Atlantic are
~60-65 knots and intersecting the coastal front pushing inland
across eastern North Carolina. As Ian continues its extra-tropical
transition, it is resulting in a WCB wrapping around Ian and
pivoting over central SC, resulting in a strengthening 700mb front
over central SC and into west-central NC. This is shown well on
SPC RAP mesoanalysis. The continuous 850mb moisture transport into
the northwest side of Ian, where robust synoptic-scale ascent is
present beneath the right-entrance region of a 250mb jet streak,
will continue to support periods of heavy rainfall over portions
of South Carolina and western North Carolina.
As Ian moves northwest, the pivoting band of heavy rainfall will
also lift northwest. MRMS instantaneous rates are generally
2-3"/hr within the heaviest band just east of I-26. 12Z HREF does
show 3-hr QPF > 3-hr FFG probabilities highest along the coast
between 18-21Z (~25-40%) with lower probabilities of 10-20% in the
eastern half of CAE's CWA. Rainfall rates should begin to diminish
to more manageable levels closer to 00Z, although some orographic
enhancement in the more elevated terrain of northwest South
Carolina and western North Carolina is possible. Additional flash
flooding is possible, particularly in poor drainage areas and in
more urbanized communities.
Mullinax
ATTN...WFO...CAE...CHS...GSP...ILM...
ATTN...RFC...SERFC...NWC...
LAT...LON 35438118 34928105 34638063 34557991 34387931
33967899 33417945 33178039 33378109 34038170
34838205 35418184
Last Updated: 324 PM EDT Fri Sep 30 2022
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