MESOSCALE PRECIPITATION DISCUSSION 0725
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 PM EDT FRI OCT 07 2016
AREAS AFFECTED...NORTHEASTERN FL...SOUTHEASTERN GA...EXTREME
SOUTHERN SC
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 071841Z - 080100Z
SUMMARY...HURRICANE MATTHEW...ADDITIONAL 2 TO 4 INCHES OF RAIN
EXPECTED THROUGH 01Z, WITH LOCALLY HIGHER AMOUNTS.
DISCUSSION...AS OF THE 2 PM EDT NHC ADVISORY, THE CENTER OF
HURRICANE MATTHEW REMAINED OFFSHORE, ABOUT 60 MILES SE OF
JACKSONVILLE BEACH FLORIDA. AT THIS TIME, THE HIGHEST RAINFALL
RATES OF ABOUT 2 IN/HR ARE CONFINED TO THE EYEWALL WHICH IS JUST
OFFSHORE OF FLAGLER AND ST JOHN COUNTIES. SATELLITE IMAGERY
INDICATE THE DEVELOPMENT OF NEW CONVECTION AROUND THE CENTER WITH
A BURST OF COLDER CLOUD TOPS NEAR 80 DEG C. RAINFALL RATES ARE
LIGHTER OUTSIDE THE EYEWALL IN THE SPIRAL BANDS, WITH HOURLY RATES
GENERALLY IN THE HALF TO THREE QUARTERS OF AN INCH RANGE.
INSTABILITY IS MARGINAL, WITH MOST UNSTABLE CAPE VALUES AROUND 500
J/KG JUST OFFSHORE NORTH OF THE CENTER OF MATTHEW.
MATTHEW IS FORECAST TO CONTINUE MOVING TOWARD THE NNW OVER THE
NEXT SIX HOURS, AND THE POTENTIAL FOR HEAVY RAINFALL WILL SPREAD
NORTH ALONG THE COAST. ENHANCED LOW-LEVEL FRICTIONAL CONVERGENCE
ALONG WITH GREATER INSTABILITY ALONG THE COAST SHOULD KEEP THE
POTENTIAL FOR THE HIGHEST RAINFALL RATES CONFINED RELATIVELY CLOSE
TO THE COAST. ADDITIONALLY, A STATIONARY FRONTAL BOUNDARY SITUATED
GENERALLY PARALLEL TO THE COAST NORTH OF MATTHEW WILL PROVIDE SOME
ADDED LIFT TO ENHANCE RAINFALL AMOUNTS. AN ADDITIONAL 2 TO 4
INCHES OF RAIN MAY FALL ACROSS THE OUTLINED AREA THROUGH 01Z, WITH
LOCALLY HIGHER AMOUNTS POSSIBLE. WHILE FLASH FLOOD GUIDANCE IS
RELATIVELY HIGH ACROSS THE OUTLINED AREA, THE DURATION OF RAINFALL
COULD SERVE TO GRADUALLY LOWER FFG VALUES, AND THE POTENTIAL
EXISTS FOR EXCEEDANCE. FLASH FLOODING IS POSSIBLE, PARTICULARLY IN
URBAN OR POOR DRAINAGE AREAS.
RYAN
ATTN...WFO...CHS...JAX...
ATTN...RFC...SERFC...
LAT...LON 33058024 32877992 32418025 32138061 31808089
31328113 30878128 30228118 29688115 29478149
29638188 29938218 30608239 31278228 32088186
32628125 32928078
Last Updated: 241 PM EDT FRI OCT 07 2016