Monthly Archives: June 2013

Flash Flood Watch continues after heavy rain today

Dual polarization radar-estimated rainfall totals for June 30th.

Dual polarization radar-estimated rainfall totals for June 30th.

A Flash Flood Watch remains in effect for the Lowcountry, including the entire Tri-County area, until early Tuesday morning as additional heavy rain is expected on top of today’s record soaking which left several communities including Summerville flooded. We may see additional rain develop as early as overnight tonight into Monday morning; more rain is a virtual certainty for Monday afternoon with highs only getting into the mid-80s before rain cools us off again. The severe weather threat is minimal but not nonzero, with occasional wet downbursts possible.

High tide is at 3:20 AM. If you live in downtown Charleston and park on the street, it wouldn’t be a horrible idea to park on higher ground tonight just in case.

So far today, the rain total at Charleston International Airport is 2.33″. This shatters the record of 1.75″ set in 1987. Barring additional rainfall before midnight, this should stand as the record.

With 13.32″ of rain, June 2013 was an incredibly wet month, but not necessarily in the top five wettest Junes on record. According to the National Weather Service in Charleston, those are:

  1. 27.24 inches in 1973
  2. 16.07 inches in 1962
  3. 16.01 inches in 1941
  4. 14.34 inches in 1963
  5. 13.76 inches in 1997

Stay aware of forecast developments and attuned to reliable warning sources in case additional Flash Flood Warnings are issued.

(Updated 4:30am 7/1 with official data from NWS climate report.)

Wet weekend ahead

Weather Prediction Center rainfall forecast through Monday morning.

Weather Prediction Center rainfall forecast through Monday morning.

Enjoy the respite this morning as conditions are ripe for numerous showers and thunderstorms capable of very heavy rainfall to develop this afternoon and through the rest of the weekend. The Weather Prediction Center forecasts an additional 2″ of rain for the Lowcountry through Monday morning with locally higher amounts. Rainfall will certainly be capable of localized flooding; keep an ear out for flood advisories if they are needed.

All this rain will knock highs back into the upper 80s, a few degrees lower than where we were over the last few days. Also, instability won’t be as great as previous days, so the severe thunderstorm threat is going to be tempered.

Tides

We’ll want to watch the tides closely this weekend for potential urban flooding issues in downtown Charleston if heavy rainfall coincides with high tide. The next two high tides in Charleston Harbor are at 1:58 PM (5.5′ MLLW) and again at 2:18 AM (5.3′ MLLW). Fortunately, guidance suggests that tides will run a little lower than predicted thanks to offshore winds, but we do need to watch rainfall timing carefully.

Unsettled weather continues Friday and through the weekend

Severe weather risk area for the southeast US Friday, June 28. Source: Storm Prediction Center; image GREarth.

Severe weather risk area for the southeast US Friday, June 28. Source: Storm Prediction Center; image GREarth.

Showers and thunderstorms will again be a consideration for Friday afternoon; the strongest ones will be able to produce some strong straight-line wind gusts and hail. The best risk for severe weather will lie inland once again today but don’t let your guard down near the coast. Today’s weather will probably be more like Thursday’s than Wednesday’s.

Before storms fire, temperatures will rocket into the low 90s with heat indices over 100. (June heat advisory criteria is 105 for 2 hours, and we won’t get anywhere near there.)

Rain chances ramp up a little more over the weekend as a dying front intrudes on SC, providing a focus for even greater coverage of showers and thunderstorms on Saturday and Sunday. It might be a great weekend to clean up around the house…

Unsettled weather is expected to continue right through the first part of next week. There are some indications, though, that the pattern will shift in time to help us dry out for the Fourth of July. It’s early yet but I’ll keep an eye on it.

Rainfall update

Charleston International Airport (the Charleston, SC official climate site) received four hundredths of an inch of rain on Thursday; much more was recorded in severe storms just ten miles north.

Rainfall totals at the airport are up to 34.25″; that’s just shy of 13″ above average for this point in the year (21.31″). We should maintain a rainfall surplus of at least 12″ especially after Saturday and Sunday’s rains which are forecast to bring another 2-3″ (with locally heavier amounts).

Unfortunately, another severe weather threat for Thursday

Here’s some preliminary wind damage and hail reports from today’s severe weather. Note that no tornadoes have been confirmed in association with the warnings on Johns Island and in West Ashley; if you have any photos that might help the National Weather Service, consider emailing them directly to the NWS via chs.skywarn at noaa.gov.

Thursday: An upper trough of low pressure with solid moisture return around the Bermuda high is going to set us up for several days of active weather as a series of disturbances are expected to swing in and stir up showers and thunderstorms, some of which will likely produce very heavy rain. Thursday may be another severe weather day, especially in the late afternoon, with plenty of instability expected to set up over the area:

NWS is particularly concerned about a piece of energy that is expected to swing by in the late afternoon; this energy will enhance lift and allow thunderstorms to produce damaging straight-line wind gusts.

Stay weather-aware tomorrow and abreast of forecast changes — will keep you posted as I can here on the blog and over on social media.

Summer sets in

Today: Isolated to scattered showers and thunderstorms mainly in the afternoon. Highs will be in the upper 80s with a few low 90s around the area. Heat indices will be a bit higher in the mid-90s. Get used to this forecast — this will be the norm for much of the week!

We may have one more coastal flood advisory this evening; high tide at 9:52. The moon’s perigee has not caused too many issues, though, and I don’t anticipate any rain around time of high tide tonight.

Jared Smith

June 23, 2013

Strong thunderstorms on radar in Dorchester County, moving north, away from the Charleston metro area.

Strong thunderstorms on radar in Dorchester County, moving north, away from the Charleston metro area.

Thunderstorms continue inland from the coast at this hour; a few may become briefly strong from Summerville westward. Currently no concerns for the immediate Charleston metro area.

Jared Smith

June 23, 2013

As I alluded to previously, a Coastal Flood Advisory has been hoisted from 7 to 11 PM; tide levels 7.2-7.4′ at Charleston Harbor expected. High tide’s at 8:57 PM. Shallow salt water flooding will occur in lower-lying parts of downtown Charleston. Don’t think we’ll have issues with street closures but usual areas, such as the Market and East Bay Street along with parts of MUSC and Lockwood Blvd may run into some salt water flooding issues tonight.

Jared Smith

June 23, 2013

Extratropical surge guidance for Charleston Harbor.

Extratropical surge guidance for Charleston Harbor.

Extratropical surge guidance, pictured above, suggests tide levels over 7′ again this evening at time of high tide (8:57 PM). We may see another coastal flood advisory issued this evening as a result. Generally speaking, coastal flooding occurs within one hour on either side of high tide. At this time, there’s no indication that rain would impact downtown Charleston or coastal areas during high tide this evening.

2:30 PM update: Storms moving inland; Lake Moultrie to be impacted

2:26 PM satellite/radar composite with temperatures. Image from GREarth.

2:26 PM satellite/radar composite with temperatures. Image from GREarth.

Showers and thunderstorms with occasional cloud-to-ground lightning are making steady progress inland this afternoon. Expect impacts soon at Lake Moultrie; this should last over the next hour. Additional showers and thunderstorms may fire across inland locations over the next several hours, especially where thunderstorms gust out and produce small outflow boundaries. Storm motions are generally from south to north around high pressure near Bermuda. Inland penetration of the seabreeze will keep beaches dry for the most part, though it’s worth watching storms about 25-30 miles offshore as they head within about 10 miles of the coast and weaken.

Remember, if you hear thunder, you should head indoors as you’re close enough to be struck by lightning.

Top temperatures so far today: 91 at Summerville Airport (closer to Ridgeville); 88 at the Charleston International Airport. We’re well into the mid-80s near the coast at this point with locally cooler temperatures at the beaches — pretty great June beach day in progress.