Monthly Archives: November 2013

Chance of strong to severe storms Tuesday (updated 8:30 AM)

8:30 AM Update: Storm Prediction Center extends slight risk throughout the Lowcountry. Damaging straight-line winds are the primary threat, with the risk of an isolated tornado or two still with us. Best chance for severe storms starts late this afternoon into the evening hours. Stay in touch with reliable, redundant sources of weather information today as the situation may change.

1:12 AM Update: Storm Prediction Center adds the Tri-County to its slight risk area. 5% tornado risk, 15% damaging wind risk within 25 miles of a point, primarily associated with prefrontal thunderstorms later Tuesday evening. There are still plenty of questions about how unstable the atmosphere is going to be Tuesday night but even meager instability could be enough with the impressive wind shear that is forecast to produce some damaging winds and perhaps an isolated tornado or two.

Original reporting:

From the National Weather Service in Charleston’s Hazardous Weather Outlook, updated at 8:38 PM Monday evening:

A POTENT STORM SYSTEM WILL AFFECT THE AREA
TUESDAY AND TUESDAY NIGHT AND COULD BRING THE POTENTIAL FOR SEVERE
WEATHER ACROSS PARTS OF THE AREA. INITIALLY…A WARM FRONT WILL
LIFT NORTH ACROSS SOUTHEAST SOUTH CAROLINA LATE TUESDAY
MORNING…AND SEVERE THUNDERSTORMS ARE POSSIBLE DURING LATE
TUESDAY MORNING INTO EARLY TUESDAY AFTERNOON…MAINLY ACROSS
SOUTHEAST SOUTH CAROLINA AND COASTAL PORTIONS OF SOUTHEAST GEORGIA.
THEN…A LINE OF SEVERE THUNDERSTORMS COULD MOVE THROUGH FROM THE
WEST AHEAD OF AN APPROACHING COLD FRONT LATE TUESDAY
AFTERNOON/EARLY TUESDAY EVENING AND CONTINUE INTO THE EARLY
OVERNIGHT HOURS TUESDAY NIGHT. THE PRIMARY RISK WITH ANY SEVERE
THUNDERSTORMS WILL BE DAMAGING WINDS AND ISOLATED TORNADOES.

The risk for severe storms will be limited by what is expected to be meager instability; however, wind shear in the atmosphere will become increasingly favorable for storms to organize and perhaps even rotate, possibly overcoming the lack of instability to pull down some strong wind gusts and perhaps a brief tornado or two. We’ll need to watch for any breaks in the clouds that might help achieve additional instability.

The better bet, though, is the chance for heavy rain at times. The atmosphere will load up with moisture from the tropics comparable to what we see on some summer days (and would be around two standard deviations above normal for late November). Believe it or not, we’re in need of some rain around here — we’re running about a 4″ deficit since September 1.

As always, it’s good to have a few reliable and redundant sources of weather info handy, just in case.

Rain will clear the area during the day Wednesday, giving way to much cooler and drier high pressure for the holiday weekend. Thanksgiving will be clear but chilly with highs not getting too far north of 50, it looks like.

Strong cold front affecting the Charleston area

A strong front is affecting the Charleston area with several reports of power outages due to downed trees on power lines coming out of Dorchester County. Wind gusts to 41 MPH have been recorded at both Summerville and Moncks Corner airports in the past hour.

Temperatures are starting to plummet from north to south. Moncks Corner has dropped 10 degrees in the last hour or so. Arctic air will continue to move into the area for much of the night with temperatures bottoming out near freezing inland and in the mid-30s closer to the coast.

The strongest winds should back off in a few hours but the National Weather Service has a Wind Advisory for the Charleston metro area through 10am Wednesday. If your travels take you over the bridges, drive very carefully as the winds will be strongest on those elevated surfaces. Keep a flashlight handy tonight in case power should go out due to strong wind gusts.

There is a small window for precipitation through 1am; however, it is highly unlikely the Charleston area will see the winter weather being observed further north in Columbia and Charlotte this evening.

On the upcoming winter preview…

A few quick notes on what to expect from our preview of winter coming up late Tuesday night through Thursday:

  • Wind chills in the mid-20s will be possible inland with very strong winds affecting the area by Wednesday morning. Bundle up accordingly! NWS has not ruled out a Wind Advisory for Wednesday. Stiff wind chills continue to be forecast for Thursday morning as well.
  • NWS notes that record low maximum temperatures will be challenged on Wednesday at least at the Charleston airport; the record there is 52 set in 1977. Current NWS forecast calls for a high of just 49. Downtown’s record is also in jeopardy; that record is 49 degrees set in 1920. Current NWS forecast is calling for 51. Expect similar challenges to record low temperatures Thursday morning.
  • A hard freeze is expected overnight Wednesday into Thursday away from the coast, bringing an abrupt end to the growing season. Prepare to bring in sensitive plants.
  • Don’t count on any snow. Any moisture that arrives just won’t be timed with the coldest air and even then drier air is going to dominate. NWS is currently carrying a 20% chance of rain late Tuesday/early Wednesday.
  • Mariners: Gale warnings are up for the Atlantic coastal waters; Charleston Harbor remains under a Gale Watch but that may yet be upgraded to a warning by morning.
  • This won’t last too long. Temperatures will begin to rebound Thursday afternoon. We’ll see the 70s again sometime over the weekend.