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Hurricane Sandy thread


usedtobe

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Thunderman, what does that graphic mean?

Yoda, Essentially the graph shows you how many standard deviations the forecast winds are from the average winds at that time of year. If the distribution is bell shaped, the 6 standard deviation wind field means this is a very rare event and that the 850 winds are rarely ever this strong at this time of year at the location where the winds are show.

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Thunderman, what does that graphic mean?

Sorry, should have explained more. It basically just shows the statistical standard deviation of the chosen parameter.

I would try to explain it, but wiki can prob do it better. Basically the higher the number the more anomalous the forecasted value is on the positive side .... the lower, the more anomalous the forecasted value is on the negative side. The +6 over NOVA/DC area correlates to an anomaly in at least the top 3% (extremely anomalous in other words).

http://en.wikipedia.org/wiki/Standard_deviation

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Yoda, Essentially the graph shows you how many standard deviations the forecast winds are from the average winds at that time of year. If the distribution is bell shaped, the 6 standard deviation wind field means this is a very rare event and that the 850 winds are rarely ever this strong at this time of year at the location where the winds are show.

What would 6 standard deviations equate to?

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SPECIAL WEATHER STATEMENT

NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC

842 PM EDT SUN OCT 28 2012

DISTRICT OF COLUMBIA-WASHINGTON-FREDERICK MD-CARROLL-

NORTHERN BALTIMORE-HARFORD-MONTGOMERY-HOWARD-SOUTHERN BALTIMORE-

PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS-CALVERT-

EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-AUGUSTA-

ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-NELSON-

ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-LOUDOUN-ORANGE-CULPEPER-

PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-

ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA-

KING GEORGE-NORTHERN FAUQUIER-SOUTHERN FAUQUIER-WESTERN HIGHLAND-

EASTERN HIGHLAND-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-HARDY-

WESTERN GRANT-EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL-

WESTERN PENDLETON-EASTERN PENDLETON-

842 PM EDT SUN OCT 28 2012

...SANDY LOCAL STATEMENT...

...SANDY TO BRING HURRICANE FORCE WINDS AND FLOOD-PRODUCING HEAVY

RAINFALL TO MUCH OF THE REGION MONDAY THROUGH TUESDAY...

THIS STATEMENT IS FOR THE GREATER BALTIMORE/WASHINGTON

METROPOLITAN AREAS, INCLUDING THE MARYLAND PORTION OF THE

CHESAPEAKE BAY, TIDAL POTOMAC RIVER, MARYLAND FROM THE WESTERN

SHORE OF THE CHESAPEAKE BAY TO GARRETT COUNTY, NORTHERN VIRGINIA,

AND EXTREME EASTERN WEST VIRGINIA. THE OBJECTIVE OF THESE

STATEMENTS IS TO PROVIDE A SINGLE PRODUCT THAT INTEGRATES THE

WARNING PRODUCTS ISSUED BY THE NATIONAL WEATHER SERVICE

BALTIMORE/WASHINGTON WEATHER FORECAST OFFICE.

SANDY LOCAL STATEMENTS WILL BE RELEASED EVERY 6 HOURS THROUGH

WEDNESDAY MORNING AT THE FOLLOWING RELEASE TIMES: 11 PM...5

AM...11 AM...AND 5 PM.

AT 8 PM EDT...THE CENTER OF HURRICANE SANDY WAS LOCATED NEAR

LATITUDE 34.0N...LONGITUDE 70.9W. THIS WAS ABOUT 475 MILES

SOUTHEAST OF WASHINGTON DC. SANDY WAS MOVING NE AT 15 MPH...WITH

MAXIMUM SUSTAINED WINDS OF 75 MPH. SANDY IS FORECAST TO MAKE

LANDFALL ALONG THE NEW JERSEY COAST MONDAY NIGHT. HOWEVER SANDY

WILL IMPACT THE REGION WELL BEFORE IT COMES ASHORE ON MONDAY NIGHT.

SUMMARY OF THREATS

------------------

THE MAIN THREATS FOR SANDY WILL BE STRONG WINDS RESULTING IN

WIDESPREAD TREE DAMAGE AND HEAVY RAINS WHICH WILL RESULT IN

EXTENSIVE FLOODING OF LOCAL CREEKS...STREAMS AND SMALL RIVERS.

BLIZZARD CONDITIONS ARE FORECAST IN THE POTOMAC HIGHLANDS AT ELEVATIONS

ABOVE 2500 FEET.

HIGH WINDS

----------

* WINDS WILL INCREASE STEADILY DURING THE DAY ON MONDAY...WITH THE

MAXIMUM WIND GUSTS OCCURRING BETWEEN MONDAY THROUGH TUESDAY

MORNING. GENERALLY...SUSTAINED WINDS OF 30 TO 50 MPH WITH GUSTS

TO 60 MPH CAN BE EXPECTED ACROSS THE ENTIRE AREA.

* HURRICANE FORCE WIND GUSTS TO 70 MPH ARE EXPECTED TO IMPACT A

REGION LOCATED BETWEEN BEL AIR MD...PT LOOKOUT MD...AND

FREDERICK MD. THIS INCLUDES THE GREATER BALTIMORE AND WASHINGTON

METROPOLITAN AREAS.

* COUPLED WITH HEAVY RAINS FROM SANDY...THE HIGH WINDS WILL RESULT

IN SIGNIFICANT TREE DAMAGE AND POWER LINE DAMAGE.

RAINFALL AND FLOODING

---------------------

* 6 TO 10 INCHES OF RAIN JUST WEST OF THE CHESAPEAKE BAY INCLUDING

THE BALTIMORE METROPOLITAN AREA.

* 4 TO 8 INCHES OF RAIN IS EXPECTED ALONG THE INTERSTATE 270

CORRIDOR INCLUDING THE WASHINGTON DC METROPOLITAN AREA.

* 3 TO 6 INCHES OF RAIN FOR THE POTOMAC HIGHLANDS AND RAPPAHANNOCK

RIVER BASIN INCLUDING CUMBERLAND MD.

* 1 TO 3 INCHES OF RAIN FOR THE NORTHERN SHENANDOAH VALLEY AND

NORTH CENTRAL PIEDMONT OF VIRGINIA SOUTH OF INTERSTATE 66

INCLUDING CHARLOTTESVILLE VA.

* THIS AMOUNT OF RAIN WILL LIKELY RESULT IN EXTENSIVE FLOODING OF

LOCAL STREAMS...CREEKS AND SMALL RIVERS STARTING ON MONDAY

AFTERNOON AND LASTING THROUGH TUESDAY MORNING.

COASTAL FLOODING

----------------

* WITH THE FULL MOON ON MONDAY...ASTRONOMICAL TIDES ARE ALREADY

HIGHER THAN NORMAL. COUNTER TO THE HIGHER THAN NORMAL

ASTRONOMICAL TIDES...STRONG NORTH AND NORTHWESTERLY WINDS ON

MONDAY WILL CAUSE A BLOW-OUT TIDE ALONG THE WESTERN SHORE OF THE

CHESAPEAKE AND THE TIDAL POTOMAC RIVER. EAST FACING BEACHES

ALONG THE TIDAL POTOMAC WILL EXPERIENCE WIND-DRIVEN WAVES THAT

WILL GIVE THE APPEARANCE OF TIDAL FLOODING AND RESULT IN SIMILAR

IMPACTS.

* AS WINDS BECOME SOUTHWESTERLY AROUND DAWN ON TUESDAY...WATER

WILL RETURN BACK INTO THE BAY AND TIDAL POTOMAC AND BEING TO

PILE UP IN THE BAY NORTH OF POOLES ISLAND AND IN THE UPPER

REACHES OF THE TIDAL POTOMAC AND ALONG SOUTH FACING SHORES.

SNOWFALL

--------

* IN THE POTOMAC HIGHLANDS ABOVE 2500 FEET THERE IS THE POTENTIAL

FOR HEAVY WET SNOW.

* THE COMBINATION OF STRONG WIND AND HEAVY WET SNOW WOULD DOWN

TREE LIMBS AND POWER LINES. NEAR BLIZZARD CONDITIONS ARE FORECAST

WITH VISIBILITY NEAR ZERO IN PERIODS OF HEAVY SNOW.

PRECAUTIONARY/PREPAREDNESS ACTIONS

----------------------------------

* BE PREPARED FOR EXTENDED POWER AND COMMUNICATIONS OUTAGES.

* IF YOU LIVE NEAR LARGE TREES...REMAIN IN THE LOWER LEVEL OF YOUR

HOME OR SEEK SHELTER ELSEWHERE IF POSSIBLE AND RIDE SANDY OUT.

* REFRAIN FROM ANY UNNECESSARY TRAVEL.

* ENSURE LOOSE ITEMS ON YOUR PROPERTY ARE SECURED.

* IF POWER LINES ARE DOWN...STAY AWAY FROM THEM AND REPORT IT TO YOUR

LOCAL ELECTRICAL UTILITY COMPANY.

* IF YOU SHOULD HAVE EMERGENCY TRAVEL...IF YOU COME UPON FLOODED

ROADWAYS DO NOT ATTEMPT TO CROSS SUBMERGED ROADWAYS. TURN AROUND

AND DONT DROWN.

* IF YOU USE A PORTABLE POWER GENERATOR...PLEASE FOLLOW

MANUFACTURERS INSTRUCTIONS AND ENSURE THAT IT IS PROPERLY

VENTILATED.

* DO NOT USE CHARCOAL GRILLS IN ENCLOSED AREAS.

* MARINERS SHOULD ENSURE THAT THERE IS ENOUGH SLACK LINE IN THEIR

BOAT`S MOORINGS TO ACCEPT A BLOW OUT TIDE ON MONDAY AND MONDAY

NIGHT.

* PERIODICALLY CHECK ON YOUR ELDERLY NEIGHBORS AND FAMILY MEMBERS

TO ENSURE THEY ARE SAFE.

* PEOPLE SHOULD HAVE ALREADY HAVE FILLED THEIR PRESCRIPTIONS AND

HAVE A FULL TANK OF GAS. IF NOT THESE PREPARATIONS SHOULD BE

RUSHED TO COMPLETION THIS SUNDAY EVENING.

FOR ADDITIONAL PRECAUTIONARY AND PREPAREDNESS INFORMATION...

PLEASE REFER TO THE DETAILED RECOMMENDATIONS RELATIVE TO YOUR

LOCATION AS FURTHER DESCRIBED BY YOUR LOCAL NATIONAL WEATHER

SERVICE OFFICE AND LOCAL EMERGENCY MANAGEMENT.

&&

.NEXT UPDATE...

THE NEXT LOCAL STATEMENT WILL BE ISSUED BY THE NATIONAL WEATHER

SERVICE BALTIMORE/WASHINGTON WEATHER FORECAST OFFICE AT 11 PM EDT OR

SOONER IF CONDITIONS WARRANT.

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Yoda, Essentially the graph shows you how many standard deviations the forecast winds are from the average winds at that time of year. If the distribution is bell shaped, the 6 standard deviation wind field means this is a very rare event and that the 850 winds are rarely ever this strong at this time of year at the location where the winds are show.

Didn't see this before. Hopefully I didn't confuse anyone ... this is a much better explanation that the one I gave.

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Because the center of the storm is still moving to the NE?

That would make sense if the back end of the precip was also moving towards the East at an appreciable rate. The bands have just been stacking up against a wall to the West all day in the same spot...

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As I told my wife a hit into NJ is a lock and this looks like it will go along with the feb 5-6th storm as one of the great modeling triumphs.

Yeah, the Euro was very good way out and all of the globals were close (at least showing a VA-north EC hit). I don't think we had long periods of crazy stuff like Spain hits or fizzles.

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As I told my wife a hit into NJ is a lock and this looks like it will go along with the feb 5-6th storm as one of the great modeling triumphs.

Someone was mentioning on Twitter that extreme blocking makes the forecast easier. Agree?

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