Understanding of meteorological terminology and concepts within NWS forecast texts (snow, warm)

[tommyFL]

For an assignment in my class, I'm researching NWS forecast text products and their function within the meteorological community. I'm analyzing the terminology within these texts and how easily these texts are understood by those who are not meteorologists.

Rate, on a scale of 1 to 10, your understanding of the terminology as well as the meteorological concepts within this forecast discussion. Please mention which terms you don't understand.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
236 PM EDT WED SEP 23 2015

.DISCUSSION...

CURRENT-TONIGHT...CONVECTIVE ACTIVITY MOVING INLAND THIS AFTERNOON
AS FORECAST BY THE LOCAL HRRR MODEL. LOCAL SURFACE ANALYSIS
CONTINUES TO DEPICT A WEAK QUASI-STATIONARY FRONTAL BOUNDARY ACROSS
THE CENTRAL PENINSULA WITH WEAK LOW PRESSURE AREA WELL OFF OF THE
VOLUSIA COUNTY COAST. THIS CIRCULATION AREA CAN BE SEEN ON NEXRAD
88D. THIS WEAK LOW IS FORECAST TO RETROGRADE INTO THE EAST CENTRAL
FL COAST OVERNIGHT. NORTHEASTERLY WINDS WILL CONTINUE TO SPREAD
SCATTERED SHOWERS/ISOLATED STORMS ASSOC WITH THIS CIRCULATION ACROSS
THE VOLUSIA COAST THROUGH THE NIGHT WHERE LOW-LEVEL CONVERGENCE
REMAINS THE STRONGEST. OCCASIONAL LIGHTNING...HEAVY DOWNPOURS AND
GUSTY WINDS UP TO AROUND 40 MPH SHOULD BE THE MAIN THREATS. DEEPER
MOISTURE LIES ACROSS THE SOUTH AND THE LOCAL HRRR MODEL SUGGESTS
OUTFLOWS FROM ACTIVITY OVER THE NORTH WILL MEET UP WITH OUTFLOWS
FROM CONVECTION MOVING NORTH FROM SOUTHERN FL. SOME STRONGER
CONVECTION LATE TODAY MAY BE FOCUSED ACROSS OKEECHOBEE...ST. LUCIE
AND MARTIN COUNTIES IF THIS ALL PLAYS OUT.

WINDS HAVE BEEN AROUND 15 MPH AND GUSTY ALONG THE VOLUSIA COAST AND
10-15 MPH ELSEWHERE. EXPECT LIGHTER WINDS TO PREVAIL THIS EVENING
AND OVERNIGHT AS THE PRESSURE GRADIENT RELAXES. LOW TEMPERATURES ARE
EXPECTED MAINLY IN THE L70S.

THU-FRI...A GRADUAL INCREASE IN DEEP LAYER MOISTURE REMAINS FORECAST
ACROSS THE AREA WITH PRECIPITABLE WATER VALUES EXCEEDING 2 INCHES. A
WEAK SURFACE TROUGH OFF OF THE SOUTH CAROLINA COAST WILL CONTINUE TO
DRIFT SLOWLY TOWARD GA/FL. PRECIPITATION CHANCES WILL ENTER THE HIGH
END CHANCE/LIKELY CATEGORY FOR EACH AFTERNOON/EVENING. COOLER AIR
ALOFT AND PERIODIC IMPULSES WILL ALSO AID IN HIGHER THAN NORMAL
PRECIP CHANCES. A LIGHT ONSHORE FLOW WILL PERSIST WITH DAILY
DEVELOPMENT OF THE EAST COAST SEA BREEZE AND SLOW PENETRATION
INLAND. ANY ACTIVITY NEAR THE COAST IN THE MORNING AND EARLY
AFTERNOON WILL LIKELY SHIFT INLAND EACH DAY BY MID/LATE AFTERNOON.
STORM STEERING FLOW LOOKS RELATIVELY LIGHT...PERHAPS OUT OF THE
S/SW...BUT MAY BE ERRATIC IN MOVEMENT AT TIMES DUE TO THE
OVERALL WEAK WIND PROFILE.

...PREVIOUS EXTENDED FORECAST DISCUSSION...

SAT-TUE... MID LVL SHORTWAVE OVER THE ROCKIES WILL COMBINE WITH THE
SHORTWAVE OVER THE NE GOMEX TO COLLAPSE WEAK MID LVL RIDGING ALONG
AND W OF THE MS RIVER VALLEY AS THE SFC RIDGE SLOWLY CREEPS INTO THE
NW ATLC. THE INVERTED TROF OVER THE ERN GOMEX/CAROLINA COAST WILL
SLOWLY LIFT UP ERN SEABOARD BUT WILL REMAIN TRAPPED BENEATH THE
RIDGE IN A TEXTBOOK REX-BLOCKING PATTERN. DEEP LYR MOISTURE WILL
REMAIN ACRS THE FL PENINSULA INTO EARLY NEXT WEEK...MODEL SOUNDING
INDICATE PWAT VALUES HOLDING BTWN 1.8"-2.2" THRU THE REMAINDER OF
THE FCST.

THE GFS CONTINUES TO LOOK PARTICULARLY WET INTO EARLY NEXT WEEK AS
AS SEVERAL MID LEVEL VORT IMPULSES EJECT FROM THE WESTERN CARIB/SE
GOMEX...ECMWF MAINTAINS A WEAKER AND LESS ORGANIZED VORT FIELD.
CURIOUSLY THOUGH...POPS ON THE THE ECMWF NUMERICAL GUIDANCE CAME IN
A LITTLE BIT HIGHER THAN THE GFS. BOTH MODELS CONTINUE TO SHOW A SFC
LOW DVLPG IN THE VCNTY OF THE YUCATAN PENINSULA ON SUN...LIFTING
NORTH INTO THE N CENTRAL GOMEX INTO TUE. GFS IS MUCH MORE BULLISH ON
ITS POTENTIAL THAN THE EURO MODEL...BUT NEVERTHELESS WILL BE AN AREA
TO WATCH.

[Cambium]

Very cool assignment! Wonder if they venture outside your area because sometimes other WFOs will use more, less, harder or easier wording.

Best advice we can give is to read it slow and reread. They use a lot of abbreviations too which can sometimes throw you off.

Hmmm. A thread on NWS Discos from all over?

[tommyFL]

Originally Posted by Cambium

Very cool assignment! Wonder if they venture outside your area because sometimes other WFOs will use more, less, harder or easier wording.

Best advice we can give is to read it slow and reread. They use a lot of abbreviations too which can sometimes throw you off.

Hmmm. A thread on NWS Discos from all over?

The assignment wasn't specifically about this; it's more to do with the role of literacy within specific communities. There was a lot of freedom to choose anything that interests you, so I went with weather.

I'm going to interview a forecaster at NWS Melbourne, so I want to use the discussion from only one WFO. Maybe this could turn into a thread about forecast discussions in general.

[Cambium]

Originally Posted by tommyFL

I'm going to interview a forecaster at NWS Melbourne, so I want to use the discussion from only one WFO.

Cool! Curious to see the question-answer text version.

Also hope others vote and mention what they think about the discussions.

[srfoskey]

What are periodic impulses?
They seem to aid in higher than normal precipitation chances, but that's about all I can gather.

[alex985]

I give it about a 5-6. I understand a lot of it but a lot of it has phrases that I haven't encountered before. I want to learn more though honestly...

[alex985]

Originally Posted by srfoskey

What are periodic impulses?
They seem to aid in higher than normal precipitation chances, but that's about all I can gather.

Maybe periodic times of higher convection? That's my only guess but I'm no expert by any means.....

[Cambium]

Originally Posted by srfoskey

What are periodic impulses?
They seem to aid in higher than normal precipitation chances, but that's about all I can gather.

COOLER AIR ALOFT AND PERIODIC IMPULSES WILL ALSO AID IN HIGHER THAN NORMAL PRECIP CHANCES.

From that sentence... Cooler air aloft helps increase instability with a warmer surface.
Impulse in physics, refers to a sudden surge of current. In this case they are referring to the upward motion otherwise known as lift. Lift happens with instability. So with the cooler air aloft and an unstable atmosphere, there will be periodic times when there is that extra upward motion (lift) to create heavier precip.

VERY hard to determine exactly where! That's why some spots will get more precip than thought or forecasted. Some Hi-Res short range models can help depict this by looking at certain parameters like the 700 vort. This is used during snowstorms as well to see where the heaviest snow will fall. But with sudden changes even "during" a storm, you have to stay on top of this parameter to see if the chances or intensity changes and even still, it might not happen as the model is depicting

This was from yesterday morning from NWS Boston. Got my eyebrow raised a couple times.

THETA-E?
ENHANCED ASCENT PER DIFFERENTIAL VORTICITY ADVECTION? (extra lift?)


FOCUS UPON THE MID-ATLANTIC LOW AND PROXIMITY TO S NEW ENGLAND...AS
TO WHETHER IT WILL MAKE AN IMPACT. WHEN WE CONSIDER A MID-LEVEL OPEN-
WAVE TROUGH AND ACCOMPANYING ENERGY YIELDING FALLING HEIGHTS ACROSS
THE REGION WOULD EXPECT THE MID-ATLANTIC LOW AND FRONTAL BOUNDARY TO
LIFT BACK N ALONG WITH HIGHER VALUES OF THETA-E. WITH N/NE QUADRANT
H8-6 FRONTOGENESIS BENEATH DECENT UPPER-LEVEL VENTING AND SOME LEVEL
OF ENHANCED ASCENT PER DIFFERENTIAL VORTICITY ADVECTION WOULD EXPECT
SOME OUTCOME ACROSS OUR AREA. SHOULD THE STRONGER N-IMPULSE THROUGH
THE BROADER CYCLONIC FLOW AND PARENT SURFACE COLD FRONT PUSH INTO S
NEW ENGLAND SOONER THERE COULD BE A GREATER MAGNITUDE OF DEFORMATION
ACROSS THE INTERIOR. WITH 23.0Z GUIDANCE THERE IS TOO MUCH VARIANCE
TO MAKE A DETERMINATION ON THE EXACT TIMING OF THE COLD FRONT. THIS
IS ALSO EVIDENT WITHIN TELECONNECTIONS. WHILE LESS-AMPLIFIED AS THE
PREVIOUS FORECASTER NOTED...THE GFS AND ECMWF HAVE BEEN IN SOME
INSTANCES OUT OF PHASE. AS A RESULT THERE IS LOW CONFIDENCE WITH
RESPECT TO THE MID-TO LATE-WEEK FORECAST.

[Wildcat15]

I too am interested to see what is said in the interview.

Had to think about what HRRR stands for, also unsure what Gomex is.

[tommyFL]

Originally Posted by G8RCAT

I too am interested to see what is said in the interview.

Had to think about what HRRR stands for, also unsure what Gomex is.

Gomex is Gulf of Mexico (really weird, that one). I have no clue about HRRR.